Abyssal Strike

The next time you hit a creature with a melee weapon attack during the spell's duration, your weapon glistens with bubbles and steam, and the attack deals an extra 1d6 cold damage to the target and causes them to be surround by tumultuous water. Until the spell ends, the target is considered to be inside difficult terrain and cannot speak.

At the start of its turn the target can make a Dexterity saving throw, escaping the water and ending the spell on a success.

At Higher Levels. When you cast this spell using a spell of 2nd level or higher, the initial extra damage dealt by the attack increases by 1d6 for each slot