As described on page 132 of the Dungeon Master's Guide, the AD&D® game world consists of many planes of existence aside from the familiar Prime Material plane. Just as physical laws operate differently in these planes, so do the effects of magic and the ways in which spells are cast. General guidelines for using wizardly magic in the various planes are given below. (If planning a campaign in one or more of the other planes of existence, or if a DM is interested in additional information about the planes, consult the Manual of the Planes.)
The Ethereal Planes[]
From the wizard's perspective, the key features of the Ethereal planes include the following:
- The effects of time occur 10 times slower than on the Prime Material plane. For instance, for every 10 turns that pass on the Ethereal planes, only a single turn has passed. Therefore, the subjective time for the wizard to memorize and cast spells is 10 times as long as the actual time required.
- The thick soup of ethereal matter restricts clear vision to about 100 yards.
- Because of the semi-solid nature of the ethereal matter, spells that create restraining effects, such as web and wall of stone, are easily circumvented by the victim—he must only move the ethereal matter out of the way. Restraining spells that inflict damage, such as wall of fire, are equally easy to circumvent, but still cause harm to the victim.
The schools of magic are affected as follows:
Abjuration: Spells of 5th level and above will not function.
Alteration: All spells of this school function normally, subject to the special laws of the Ethereal planes.
Conjuration/Summoning: Entities from the Prime Material, Astral, and outer planes cannot be summoned. Leomund's secret chest places the conjured chest in a location in the Ethereal plane different from that of the caster.
Divination: These spells function only if the wizard is in the area between the Prime Material plane and the Ethereal planes (called the Border Ethereal) and is casting the spells into one of the adjacent planes. For instance, detect magic will not work in the Ethereal plane, but it functions normally if cast from the Border Ethereal into the Ethereal planes. Contact other plane, however, functions everywhere in the Ethereal planes.
Enchantment/Charm: All spells of this school function normally, subject to the special laws of the Ethereal planes.
Invocation/Evocation: All spells of this school function normally, subject to the special laws of the Ethereal planes, except that materials created by evocation spells are made of ethereal matter and have the properties of that matter. Bigby's forceful hand, for instance, will not stop an opponent.
Illusion/Phantasm: All spells of this school function normally, subject to the special laws of the Ethereal planes. However, illusionary images and items do not disappear at the end of the spell's duration, or when the wizard stops concentrating, or when the illusion is touched. Instead, the images and items gradually fade away. Invisibility, change self, and fear are not subject to fading and function normally.
Necromancy: All spells of this school function normally, subject to the special laws of the Ethereal planes.
Magical Items: Pluses on weapons are reduced by one to attack and damage rolls (a sword +2 effectively becomes a sword +1 ). Armor and protective devices are likewise reduced by one plus. Magical items that duplicate specific types of spells operate under the same restrictions as described above.
The Inner Planes[]
From the Wizard's perspective, the key features of the Inner planes include the following:
- Spells that rely on elemental forces can be modified to affect all other elemental types, though each modification must be researched separately. For instance, a spell that affects water can be used to similarly affect earth or fire, so that a wall of water may appear or create air can be cast. To determine if a modified spell can be cast, the wizard must roll against his Intelligence as if learning a new spell. If the roll fails, the wizard cannot make another attempt for one full day (as measured on the Prime Material plane). These modified spells can be used only in the inner planes.
- Modified spells apply only when modifying one elemental spell to another. Positive and negative energies are not eligible. For instance, a wizard cannot create a wall of negative energy.
- In the plane of Fire, all material created by spells (such as water and ice) is immediately affected by the extreme heat. For instance, the ice created by ice storm immediately melts.
- In the plane of Water, spells are affected as described in the Casting Spells Underwater section above.
- In the Energy planes, matter created by spells is destroyed one round affect its creation. Spells that inflict variable amounts of damage in the plane of Positive Energy, and minimum damage in the plane of Negative Energy. Spells that inflict damage over a period of several rounds function for only one round.
The schools of magic are affected as follows:
Abjuration: All spells of this school function normally, subject to the special laws of the inner planes, except where noted in the spell description. Spells affecting extra-dimensional creatures do not affect creatures native to the inner planes. When the anti-magic shell is used in the inner planes, all magical protections are removed from within that sphere, removing any protection the user may have to survive in that plane.
Alteration: These spells are the most likely to be modified as described above. A lower water spell, for instance, can be modified to lower fire in the plane of Fire, and airy water could be modified to airy fire. Here are a few special cases:
- Transmute rock to mud can function as transform element to para-element; earth becomes ooze or magma, fire becomes magma or smoke, air becomes smoke or ice, and water becomes ice or ooze. Each type of transmutation must be researched separately.
- Transmute water to dust can be modified to transform element to negative quasi-element; elemental water becomes ash, air becomes vacuum, fire becomes ash, and earth becomes dust.
- Astral spell will not work in the inner planes.
Conjuration/Summoning: Usually, spells summoning a particular type of elemental creature summon that being only in its native plane. These spells do not guarantee control over the summoned elemental, but the elemental is not immediately hostile to the caster. Spells summoning animals, monsters, or other Prime Material creatures instead summon the elemental versions of these creatures. Elemental creatures have the same appearance and abilities as their Prime Material counterparts, but are elementals of that type found in that inner plane (except that the Positive and Negative planes have no elemental types).
Spells that contact beings in the Astral and outer planes do not function in the inner planes.
Divination: These spells function normally. Those that call on an entity function only if that entity is native to the inner planes or Ethereal planes.
Enchantment/Charm: These spells function normally. Hold person and charm spells work only against humanoid elementals.
Illusion/Phantasm: These spells function normally.
Invocation/Evocation: Usually, invocation spells function only if the entity's domain is in the same plane as the wizard. Evocation spells dealing with elemental forces can be modified to call upon any elemental force. These include spells that create items of fire, lightning, ice (but not cold), winds, clouds, fog, and flames. For instance, a fireball can be modified into a lightning ball or earth ball, and lightning bolt can be modified into fire bolt or air bolt; in all cases, the range and damage remain the same. Note that spells such as cone of cold and wall of iron cannot be modified, since they have no actual elemental basis.
Necromancy: Beneficial necromantic spells restore hit points, abilities, levels, or life. Harmful necromantic spells deprive victims of these quantities. Beneficial necromantic spells will not function in the Negative plane, while harmful spells automatically succeed and inflict maximum damage. Beneficial spells restore the minimum number of hp in the negative quasi-planes, and those spells that require a saving throw or are based upon Constitution automatically fail; harmful spells automatically succeed and inflict maximum damage. Beneficial spells automatically succeed and operate to their maximum ability in the positive quasi-planes; harmful spells inflict minimum damage and saving throws of 2 or greater automatically succeed against these spells. Beneficial spells in the Positive Material plane automatically succeed and operate to their maximum ability; harmful spells automatically fail.
Magical Items: Weapon pluses are reduced by two to attack and damage rolls (a sword +3 effectively becomes a sword +1 ). Exceptions include those with pluses against particular elemental creatures and those that draw their power from elemental planes, such as energy draining swords. Armor and protective devices are likewise reduced by two pluses. Magical items that duplicate specific types of spells operate under the same restrictions as described above
The Astral Plane[]
From the wizard's perspective, the key features of the Astral plane include the following:
- Items or matter created by spells are affected by the plane's weightless environment. For instance, water forms into circular balls; when touched, these liquid balls flow over the victim in a light film. Liquids that inflict damage, such as acid, inflict twice their normal damage, and victims covered in liquid film cannot speak without letting the liquid into their lungs and drowning in 1-4 rounds. Victims covered in liquid cannot use spells with verbal components (unless they are affected by water breathing or a similar spell or device that allows them to breathe underwater). The liquid can be removed by extensive toweling, entering a plane where gravity exists, or spinning the victim fast enough so that the liquid is flung from his body.
- Fires burn in circular flames without consuming their fuel sources. Wall of stone and other wall spells, along with other spells that create surfaces, generate hollow spheres with radii of 10 feet plus 2 1⁄2 feet per level of the caster, regardless of the listed area of effect. Temperature is poorly conducted in the Astral plane, so spells generating heat and cold do not affect those outside the spell area.
- A wizard cannot move or dodge while casting spells; if already moving, he must continue moving with the same speed and in the same direction as the previous round in order to cast the spell.
- Spells that require access to the Ethereal or inner planes will not function.
The schools of magic are affected as follows:
Abjuration: These spells work normally, except that they cannot affect the fabric of the Astral plane itself; the plane cannot be dispelled or held back. Dispel magic affects astrally projected travelers by casting them back to their original bodies; it has no effect if cast against the plane or against silver cords.
Alteration: Alteration spells that contact the Ethereal and inner planes or make use of extradimensional space will not work, such as vanish and rope trick.
Objects animated by alteration spells have an Intelligence of 0 for movement purposes, but they can attack creatures adjacent to them. Spells that modify movement function only in situations where that movement is permitted in the Astral plane. For instance, fly only works in balls of air, jump only works if the subject can push against solid objects, and slow and haste affect only muscular movement (likewise affecting combat) but have no affect on mental concentration movement. Alteration spells that control or modify conditions operate only if the conditions already exist; wizards cannot call these conditions into existence.
Conjuration/Summoning: Conjuration/Summoning spells of 5th level or higher do not function unless linked with abjuration magic (for instance, a spell belongs to both the conjuration and abjuration schools). Summoning cantrips will not operate, but conjuration cantrips will. Spells that call for the direct intervention of an entity will not work unless the entity is a native of the Astral plane.
Enchantment/Charm: Spells cannot call into being creatures from other planes. Spells that manipulate or call into being extradimensional space in the Astral plane do not function, such as deeppockets.
Divination: Because of the inherent magic of the Astral plane, detect magic causes the entire plane to radiate magic; there is only a 5% chance for detecting a specific magic radiation against this background. Spells such as true seeing and devices such as the gem of seeing reveal the fully infinite nature of the Astral plane, an experience that can overwhelm the viewer. The chance of being overwhelmed is 100% minus 5% per level of the viewer. Those overwhelmed are immobilized for the duration of the spell or for 1-6 true turns if viewing through a device.
Illusion/Phantasm: Illusionary spells and phantasm spells with an illusionary component function normally, but phantasm spells without an illusionary component will not function. For instance, phantom steed will not work because the spell has no illusionary component, but phantasmal force can be cast, since it has an illusionary component.
Invocation/Evocation: These spells function normally, except as modified by the physical laws of the Astral plane (see the explanation of the effects of a weightless environment above). The spells created by the archmage Bigby function differently when cast against creatures that are moving by mental concentration (those moving physically—such as by pushing off objects—are affected normally).
- Interposing hand: Those of lesser Intelligence than the caster are stopped, others are slowed in movement by 50%.
- Forceful hand: If the caster has a higher Intelligence than the affected creature, the caster controls the speed and direction of the creature. Equal or greater Intelligences result in no movement.
- Grasping hand: This operates the same as the interposing hand if the caster's Intelligence is equal or less than that of the victim, but it repels the victim as a double strength forceful hand if the caster has higher Intelligence.
- Clenched fist and crushing hand function normally.
Necromancy: These spells function normally. However, a clone created on the Astral plane requires 1,000 years to grow for every day it would take to grow on the Prime Material plane. Therefore, if a clone needed two months to grow on the Prime Material plane, the same clone would require 60,000 years to grow on the Astral plane.
Magical Items: Weapons are reduced by one plus to their attack and damage rolls (a sword +2 effectively becomes a sword +1). Exceptions include those with pluses against astral creatures. Armor and protective devices are likewise reduced by one plus. Magical items that duplicate specific types of spells operate under the same restrictions as described above.
Normal potions in normal vials have the viscosity of syrup and tend to cling to the sides of the vials; such potions require 1-4 rounds to consume with a 5% chance that the drinker chokes (no damage, but the drinker loses the effects of the potion). Drinking potions from wineskins or soft flasks avoids this difficulty and allows normal consumption.
Magical items that tap into extradimensional space or the Ethereal or inner planes do not function in the Astral plane, nor do items that call upon powers from those planes.
The Outer Planes[]
From the wizard's perspective, the key features of the outer planes include the following:
- Spells that require access to powers and creatures in the inner planes and Prime Material planes do not function (unless otherwise noted below).
- Cantrips will not function.
- Creatures and phenomena native to the outer planes are unaffected by Prime Material planar spells that summon, communicate, control, or prevent entry. Comparable spells exist for each plane, but they must be learned by the wizard in that plane; animal growth for animals of Elysium is an example. These are not considered modifications of existing spells, but different spells altogether.
The schools of magic are affected as follows:
Abjuration: These spells are useless against beings native to the plane the wizard is in (for instance, protection from evil has no effect on the evil occupants of the Nine Hells). However, dispel magic disrupts spells cast by creatures native to the outer planes.
Alteration: The Chaos planes (Happy Hunting Grounds to Tarterus, inclusive) have a random effect on alteration spells that create matter (such as fog cloud) or change matter into other shapes (the various polymorph spells). The chance of a random effect depends on the plane (see Table 10).
| Plane | Chance of Random Effect |
|---|---|
| Happy Hunting Grounds | 20% |
| Tarterus | 20% |
| Olympus | 40% |
| Abyss | 40% |
| Gladsheim | 60% |
| Pandemonium | 60% |
| Limbo | 80% |
Created matter subject to a random effect has its appearance altered; for instance, a fog cloud might be blue in color or sparkle like diamonds. The change does not affect the properties of the matter. The DM determines the nature of the change.
The random effect for a spell that alters the shape of matter is that the spell may not function at all, or that it may function in an unintended matter. Roll 1d100 on Table 11 if such a random effect is indicated.
| d100 Roll | Effect |
|---|---|
| 1-10 | Target does not change in appearance or properties. |
| 11-30 | Target changes in appearance (as determined by DM), but retains all the properties of the original. |
| 31-50 | Target does not change in appearance, but gains the properties of the new form. |
| 51-70 | Target changes to resemble some nearby random object or creature, but retains the abilities of its original form. |
| 71-90 | Target changes to resemble some nearby random object or creature, and gains the abilities of that object or creature. |
| 91-00 | Target changes in form and function into something not in the immediate area. (DMs are encouraged to be fiendish.) |
Conjuration/Summoning: Non-native beings cannot be summoned unless they are in adjacent planes or planar layers. Creatures native to the plane can be called upon, but they are not controlled by the wizard; any tasks given such creatures must be negotiated. Protective spells that are effective in the Prime Material plane do not function against native creatures.
Find familiar will bring an imp, quasit, brownie, or pseudo-dragon. The DM is free to add other suitable candidates or to modify the appearance (but not the abilities) of these familiars.
Enchantment/Charm: Spells directed toward specific creatures (such as charm person) will not function against their outer planar equivalents. Planes other than the one occupied by the wizard cannot be accessed, though extradimensional space can be (so spells such as deeppockets function normally, but spells such as shadow walk will not). Magic jar or any similar spell that leaves the caster's original body unoccupied creates the risk of that body being occupied by a native of the other planes (see the Necromancy entry below for details).
Divination: Spells that detect or identify mainly respond to the alignment of the plane, overwhelming the alignment of any beings in the plane. For instance, if a good warrior is in the Nine Hells, know alignment is overwhelmed by the plane's evil nature and will not reveal that the warrior is good. However, a detect good will reveal the warrior's goodness.
Illusion/Phantasm: These spells function normally, though the caster should keep in mind that many of the powerful beings inhabiting these planes are immune to illusionary attacks and effects. However, spells that rely on demi-shadow magic and shadow magic function at half strength and half effects. Shadow monsters, for instance, creates creatures with half the standard hit points that inflict half the standard damage when attacking; shadow magic inflicts only half damage and effects.
Invocation/Evocation: These function normally, although they may be changed due to prevailing conditions in a particular plane. Generally, these changes are similar to those experienced in the inner planes. For instance, a wall of ice will begin to melt immediately in the heat of the Nine Hells.
Necromancy: These spells have no effect on the natives of the planes. Reincarnation causes revived individuals to be of the same alignment as the plane; for instance, a PC reincarnated in the Nine Hells will be evil. Spells that involve a body uninhabited by a spirit, such as magic jar, have a 1 percent chance per day per depth of layer of being inhabited by native spirits. For instance, a character who died on the eighth layer of the Nine Hells has an 8 percent chance per day of his body being occupied unless it is raised, while a body on the 100th level of the Abyss has a 100 percent chance of being occupied on the first day). The spirits will not voluntarily release the body (a limited wish or spells of similar power will dispel them).
Magical Items: Weapons are reduced by one plus for each plane they are taken through; this applies only when moving from plane to plane, not when moving through planar layers. If a weapon becomes non-magical, all special abilities are lost. These penalties do not apply to weapons designed to affect particular creatures of the outer planes. Armor and other protective devices are similarly affected. All other magical items suffer the same limitations as the spells they mimic. Magical items that reach into extradimensional space function normally, but those that draw power from the inner planes or access the Ethereal planes do not function.
Casting Spells When the Caster is Impaired[]
Impaired Vision[]
A wizard's vision can be permanently or temporarily impaired as a result of blindness (magical or natural), disease, poison, or physical damage. Vision is also impaired in darkness.
The ability to see is not crucial in the casting of many spells. For instance, mirror image, monster summoning, tongues, and comprehend languages (when used to translate spoken words) do not require the wizard to be looking at anything in particular, and can therefore be cast with impaired vision. However, spells such as read magic, detect invisibility, and comprehend languages (when used to translate written words) that require the wizard to be looking at a particular object or location cannot be cast with impaired vision.
Impaired vision has no effect on spells the wizard casts on himself, such as change self or armor. Likewise, impaired vision has no effect when the wizard is attempting a touch spell (such as protection from evil) on a willing subject, presuming the wizard is close enough to the subject to touch him. However, if a wizard attempts to use a touch spell on an unwilling subject, the wizard must make a successful attack roll with a -4 penalty (this assumes that the wizard is close enough to his intended subject to touch him). As with all attacks, the DM can modify this roll if the victim is unprepared for the attack or is unaware of it. If the roll succeeds, the wizard touches the subject and the normal spell effect occurs.
Spells that are cast on a specific person, place, or thing from a distance, such as charm person or magic missile, cannot be cast by wizards with impaired vision. A wizard cannot simply blast a magic missile in a general direction and hope for the best—the spell does not operate that way. Knowing the exact destination of these types of spells is a vital element of their execution.
Spells that are cast over a general area can be cast by wizards with impaired vision, although their effects may not be as precise as they would be if the wizard could see. For instance, a wizard with impaired vision could cast flaming sphere in front of himself and direct it to move straight ahead toward an area where he hears a group of screeching goblins. But if the goblins scatter at the approach of the flaming sphere, the wizard will not be able to accurately direct its movement to run them down.
This limitation also holds true for illusion spells that create illusionary images, such as phantasmal force; at best, the illusionist is making a rough estimate as to the location of his illusion, and any adjustments he makes to the illusion (such as moving it or having it respond to the actions of other characters) is unlikely to be more than an educated guess.
Additionally, the vision-impaired wizard is creating visual illusions from memory, and the results might not always be as precise as they would be if the wizard could see. In general, the more complex the illusion cast by a vision-impaired wizard, the more easily the illusion will be disbelieved by an opponent; the DM is free to add as much as a +4 bonus to the saving throws of opponents attempting to disbelieve such illusions (see pages 81–82 of the Player's Handbook for details on adjudicating illusions, and the section on illusions in Chapter 7 of this book).
Vision-impaired wizards can use their familiars for information about their surroundings, thus enabling them to cast spells with more accuracy and precision. Wizard eye and similar spells can help a vision-impaired wizard to "see." Infravision is not always useful in these situations, since it works to enhance the wizard's natural vision (although infravision helps if the wizard's vision is impaired because of darkness, and not because of disease or damage). The non-weapon proficiency Blind Fighting is equally ineffective for the vision-impaired wizard.
Impaired Hearing[]
A wizard's hearing can be permanently or temporarily impaired as a result of deafness (magical or natural), disease, poison, or physical damage (such as repeated exposure to loud noises). Unlike the vision-impaired wizard, the hearing-impaired wizard has only modest limitations on his spell casting abilities.
Although most spells have a verbal component, it is not necessary for the wizard to clearly hear the words or sounds he utters to cast a spell. These sounds serve to release magical energies which in turn trigger specific reactions; as long as the wizard utters the correct sequence of sounds, it makes no difference if he actually hears the sounds himself. Note that a silence spell prevents the casting of any spells with verbal components, since silence prevents the sounds uttered by the wizard.
Spells that require the wizard to hear, such as comprehend languages (when used to translate speech), are ineffective for hearing-impaired wizards. Spells that create sounds, such as alarm, are able to be cast, but the impaired wizard will not hear the effects.
Hearing-impaired wizards casting illusions with audible elements may encounter the same problems as vision-impaired wizards. The audible elements of such illusions will have to be educated guesses, based on the wizard's memory of actual sounds. As with illusions cast by sight-impaired wizards, the more complex the illusion cast by a hearing-impaired wizard, the more easily the audible element of the illusion will be disbelieved by an opponent. The DM is free to add as much as a +4 bonus to the saving throws of opponents attempting to disbelieve such illusions. A hearing-impaired wizard cannot use his familiar to serve as surrogate "ears" to enable him to cast such spells with more precision or accuracy
Impaired Speech[]
A wizard's ability to speak can be impaired as a result of disease, magic (such as a silence spell), or physical damage. A gagged wizard will also be unable to speak. No spell with a verbal component can be cast by a wizard with impaired speech; he must be able to enunciate each phrase or sound of a spell's verbal component clearly and distinctly for the spell to be successful. Ventriloquism cannot substitute for an impaired-speech wizard's voice when he attempts to speak a spell's verbal component; ventriloquism is useless to a speech-impaired wizard, since it is an extension of sounds the wizard is normally able to make.
Similarly, an impaired-speech wizard cannot use his familiar to speak verbal components, including those familiars capable of speech, since spells only operate if the wizard himself utters their verbal components.
However, an impaired-speech wizard can use the spell vocalize to allow him to cast spells that normally require a verbal component. Casting these spells must take place within the duration of the vocalize spell. (For more about vocalize, see Chapter 9. ) According to the Player's Handbook (pages 85–86), the use of components is an optional rule. If components aren't used for spell casting in your campaign, it is assumed that the caster must be able to speak in order to cast any spell (see the first paragraph in the Casting Spells section on page 85 of the PH ). Vocalize can still help a speech-impaired wizard if the components rules are not in use; otherwise, all of the rules for speech-impaired wizards apply.
Impaired Movement[]
Many spells require somatic components (gestures or movements). If the wizard is unable to move his hands (because of damage, a magical effect, or physical restraint) he may be unable to cast a spell that requires hand movements. If a spell specifically requires hand movements, the wizard isn't allowed to substitute another method. He cannot just wiggle his ears or rock his head in place of the required hand movements, nor can he use a familiar or other character (or animated object) to act as his surrogate to execute them. If a single finger is the requirement for a somatic component (for instance, if the wizard needs to point at the target of his spell), then he needs only one free hand to cast the spell; otherwise, either hand (or any finger) will suffice.
Note that a movement-impaired wizard also might have difficulty with spells requiring material components. If the wizard has his hands tied, he may not be able to reach the necessary material components inside his back pack or mingled with other items in a deep pocket in his robe. Even if he manages to fish them out, certain spells may require him to manipulate the material components in a certain way (he might be required to rub the components together or hold them flat in his hand; protection from evil requires the caster to trace a three-foot-diameter circle on the ground with powdered silver). If he cannot manipulate the material components as required, the spell will not work. When a wizard acquires a new spell, the DM should clarify its casting procedures.
Remember that the use of components is an optional rule. If components are not used for spell casting in your campaign, assume that the caster must have both arms free in order to cast any spell (see the Casting Spells section on page 85 of the PH ). Any combination of hand movements and gestures will suffice.
Impaired Concentration[]
The successful casting of a spell requires intense, uninterrupted concentration from the caster. If the caster's concentration is interrupted by an attack, a sudden noise, or any other distraction, the spell is lost.
In certain situations, the caster may have trouble focusing or sustaining his concentration. He may be suffering from an extreme headache or other illness. He may be dizzy, fatigued, or otherwise disoriented. Or he may have had a little too much wine and is feeling the after-effects. In such cases, the DM can rule that the wizard is unable to cast spells as effectively as he normally would. In extreme cases—for instance, if the wizard's headache is so severe that he is unable to stand or open his eyes—the DM might rule that the wizard is completely unable to cast spells until his condition improves.
In less extreme cases, the DM can require the wizard to make a successful Intelligence Check before attempting to cast any spell to see if he can muster the necessary degree of concentration. After the wizard announces which spell he will attempt to cast, the player rolls 1d20. If the result is less than or equal to the wizard's Intelligence, the spell is cast normally. If the result is greater than the wizard's Intelligence, the spell is lost.
The DM might wish to add a penalty or bonus to these Intelligence Checks. For instance, if the wizard is disoriented as a result of falling out of a tree and landing on his head, the DM might require a -2 modifier to his Intelligence Checks prior to casting his spells.