Skimming

Weapon (any thrown or ranged), uncommon

A skimming weapon skips across the surface of liquid when thrown, or slices cleanly through it when thrown at a target below the surface.

Water provides no protection against attacks with a skimming weapon, and if you also are fully or partially submerged a skimming weapon returns to you after the attack. If there is a liquid surface between you and your target when the weapon is thrown, you can spend a bonus action to skip the weapon off that surface, allowing you to either increase the weapon’s range increment by 10 feet for that attack or to alter the weapon’s trajectory in mid-flight, allowing you to treat any square of the liquid’s surface within range as the weapon’s point of origin for the purpose of determining whether the target has cover.