Wave Cutter Sword

The wave cutter would be a sword variant (of any sword) that could only be found in underwater structures. It would look like the normal kind, but with a wave shape at the end.

It would also function normally except if you hit the water's surface with it, it will create a wave that travels 28 blocks before disappearing. This wave deals 5 damage and huge knockback, but maybe enchantments could upgrade it.

This sword also has an extra function. While above water with no barrier between you and it, or while swimming on the water's surface, you can use it as a surfboard. You can also do this on lava with the netherite version