Brain Freeze

You freeze the mind of a creature in the process of casting a spell. Make a spell attack against the target. If you hit, you deal 2d8 cold damage, and the target must make a Constitution saving throw to continue casting the spell, as if they took damage while concentrating on a spell. If they fail, the spell fails and has no effect.

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the cold damage increases by 1d8 for each slot level above 4th.