Backlash(Spell Compendium, p. 23)
Level: Sorcerer 4, Wizard 4, Spellthief 4,
Components: V, S,
Casting Time: 1 standard action
Target: Creature touched
Duration: 10 min/level or until discharged
Saving Throw: Will negates
Spell Resistance: Yes
You touch your opponent and a red aura entwines him, then fades without further effect. You back away as your opponent laughs and begins to cast a spell.
The first time the target creature attempts to cast a spell or use a spell-like ability, the magic of that spell backfires. The spell is expended, and the creature takes 1d6 points of damage per level of the spell being cast. This discharge ends the spell.