Tidal Wave

Casting Time: 1 action
Range: 120 feet
Duration: Instantaneous
You conjure up a wave of water that crashes
down on an area within range. The area can be
up to 30 ft. long, up to 10 ft. wide, and up to
10 ft. tall. Each creature in that area must make a Dexterity saving throw. On a failure, a creature
takes 4d8 bludgeoning damage and is knocked
prone. On a success, a creature takes half as much damage and isn't knocked prone. XGE, pg. 168.