Zippit!

In response to a creature vocalizing, you make a sharp sound and hold a finger up in an attempt to interrupt them. The target must succeed on a Constitution saving throw or become silenced as its mouth is fused shut for the duration. If you silence a target that is casting a spell with verbal components, the target’s spell slot isn’t expended, but its action is wasted.   At the end of each of its turns, the target can make a Strength saving throw as it tries to tear open its mouth. On a success, the target takes 1d8 slashing damage and is no longer silenced. Alternatively, as an action, the target can use a bladed implement to cut open its mouth, taking 1d8 slashing damage and ending the silence.   At Higher Levels. When you cast this spell using a spell slot of level 4 or higher, the damage increases by 1d8 for each slot level above 3.