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Disruptive Spell (Metamagic)
Your magical energies cling to enemies, interfering with their spellcasting.
Benefit: Targets affected by a disruptive spell must make concentration checks when using spells or spell-like abilities (DC equals the save DC of the disruptive spell plus the level of the spell being cast) for 1 round. Targets that avoid the spell's effects avoid this feat's effect as well. A disruptive spell uses up a spell slot one level higher than the spell's actual level.