Only a normal animal (including a giant version) can become an animal spy. This spell enables the caster to share the animal's senses: see through the animal's eyes, hear with its ears, smell with its nose, and so on. The animal is completely unaware of the spell's effect, unless the druid warns the beast before casting. Animal spy grants no control over the creature. However, most casters use it on a trained animal or one befriended with the animal friendship spell.
An animal with a special bond to another, such as a familiar, receives a saving throw vs. spell to negate the effect if unwilling to submit to the casting or unaware.
For the duration of the spell, the caster remains in a trance, unable to move or use human senses. This can prove dangerous; for instance, those attacked while using the spell cannot feel injuries to their bodies. However, at the start of any round, the caster can return the animal's senses to the creature and resume control of the human body. This decision ends the spell immediately. The spell also ends if the animal travels more than 100 yards away per caster level.
Notes: Uncommon for druids; rare for other nature priests.