Guardian of the Deep

The Guardian of the Deep is an elite crab boss found in the Forgotten Pool of Blackfathom Deeps.

Adventure Guide
'' Underneath the cursed Moonshrine Ruins, ancient creatures battle for territory. Old Serra'kis was driven from the ruins by The Guardian of the Deep who was seeking new spawning grounds. Now, the Guardian watches over thousands of eggs until they can hatch, and spread throughout the waterways of Azeroth.''