Water Whip

You create a long tendril of water that lashes out at your command toward a creature in range. Make a melee spell attack against the target. If the attack hits, the creature takes 1d6 slashing damage, and if the creature is Large or smaller, they must succeed on a Strength saving throw against your spell save DC or be knocked prone. 

The spell's damage increases by 1d6 when you reach 5th level (2d6), 11th level (3d6), and 17th level (4d6).