Riverine Blade

Weapon (longsword), rare

The crossguard of this distinctive sword depicts a stylized garroter crab (see Tome of Beasts) with claws extended, and the pommel is set with a smooth, spherical, blue-black river rock. You gain a +2 bonus to attack and damage rolls made with this magic weapon. While on a boat or while standing in any depth of water, you have advantage on Dexterity checks and saving throws.