Cruel Counter

You interrupt a creature in the process of casting a spell. If the spell being cast is of 4th level or lower, it fails. If the spell being cast is a 5th level or higher spell, make an ability check using your spellcasting ability. The DC equals 13+ the spells level. Ona success, the creature's spell fails (having no effect) and it must make a Wisdom saving throw against your spell save DC. On a failed save, the creature takes 2d8 psychic damage, and no damage on a successful save.

When you cast this spell using a spell slot of 5th level or higher, the interrupted spell has no effect if its level is less than or equal to the level of spell slot you used. And, the damage increases by 1d8 for each spell slot used above 4th, up to 6d8.