In areas where jackal wizards are known to operate, it is wise for an Arabian wizard to protect himself from spell thievery. This spell serves this purpose admirably.
After the spell is cast, the wizard simply places a small coin (the spell's material component) in his turban or other headgear. If a jackal wizard attempts to lift a spell from the protected wizard, the coin grows warm, warning the wizard.
The first attempt to steal a spell from a wizard protected by the jackal ward will always fail. The second and subsequent attempts have a 50% chance of being foiled.
Notes: Common for spellcasters from an Arabian setting; otherwise very rare.