Countermancy

You attempt to alter reality to negate a spell of 6th level or lower  that's in the process of being casted. Upon activating this spell, you must quickly guess what school of magic the spell you're trying to negate is. On a correct guess, the spell you're targeting instead creates a harmless effect such as a few bubbles or butterflies. On a failed guess, this spell fails and you take 2d4 psychic damage. This spell does not affect spells without a somatic component.

When you cast this spell using a spell slot of 7th level or higher, you can attempt to negate the spell if its level is less than or equal to the level of the spell slot you used.