BackLash (EFA - B)

You touch a creature and a magical aura entwines it before it fades from view. Make a melee spell attack against a creature. The first time the target attempts to cast a spell, the magic of that spell backfires. The spell slot (or daily use for Innate Spellcasters) is expended, and the creature takes 1d8 psychic damage per level of the spell cast. Once backlash rebounds a magical attack, its duration ends.