Water Slash

Can only be learnt in the plane of water or by DM discretion)

This spell acts as a cantrip and can only be used underwater.

You slash at one creature within range with some water. Make a ranged spell attack against the target. On a hit, the target takes 1d6 slashing damage. 

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