Water Blade

You take the force and essence of a tidal wave and hone it to an edge of pure clean freezing water. Make a melee weapon attack at a target adding the water Blade to it. On a hit the target takes an extra 2d8 cold damage from the attack. In addition as the force of the crashing wave hits them, the target must make a Dexterity saving throw. On a failed save, the creature is knocked prone.

Using a Higher-Level Spell Slot. The damage increases by 1d8 for each spell slot level above 1.