S02:E12 - Twenty Thousand Leagues Under the Fishbowl!

An impending ecological disaster involving a sunken oil tanker on the lip of an underwater volcano sends the city into a panic. Nia's uncle Captain Abbott is to lead an submarine mission to raise the tanker before it can explode. But things take a strange twist when Admiral Bubbles uses a home-made device to switch his brain into Beanie's body, and vice versa!