I just thought of something amazing.

What if Jerry gets nicknamed the Kraken?! Since Jerry has tentacles. In the Mermaid au he could be a baby octopus (they're fucking tiiiiiny) and when he gets big, big, big, like Angelo and Lucifer. He could get nick named the Kraken. (He accidentally shows himself on the surface and mayyyybe attacks a ship for getting too close) or maybe not an octopus and it can just be a special type of Mermaid