Storm Crab

Storm Crab
Storm crabs are colossal crustaceans with four monstrous claws and a poisonous stinger. Equally adept underwater or on shore, they can exhale a jet of pressurized water to crush foes.
Giants on some worlds claim Stronmaus or one of his children created storm crabs in the early years of an ancient empire. Just as behirs were created to fight dragons on land and rocs to challenge dragons' mastery of the sky, storm crabs were meant to battle dragon turtles, bronze dragons, and other aquatic foes. On many worlds, these creatures fiercely guard the underwater strongholds of storm giants, as well as the ruined keeps giants have abandoned.
Given all the weird things that swim in the deep ocean, who am I to complain about a colossal crab with a poison stinger that can knock you away with a high-speed jet of water?