Drown

You cause a creature's lungs to fill with seawater. Unless the target makes a successful constitution saving throw, it immediately begins suffocating. 

A suffocating creature can't speak or perform verbal spell components. It can hold it's breath for a number of rounds equal to 1 + its constitution modifier (minimum of 2) after which it drops to 0 hit points and the spell ends. Huge or larger creatures are unaffected, as are creatures that can breathe water or don't require air.

A suffocating (not dying) creature can repeat the saving throw at the end of each of its turns, ending the effect on a success.

When you cast this spell using a spell slot of 4th level or higher, you can target one additional creature for each slot level above 3rd.