Coercive Spell( Drow of the Underdark, p. 47)
Living foes damaged by your spell become more pliable and vulnerable to your commands.
You can alter a spell that deals damage to foes so that any living creature dealt damage by the spell takes a —2 penalty on Will saves for 3 rounds.
Penalties from multiple coercive spells do not stack. A coercive spell uses up a spell slot one level higher than the spell's actual level.