Storm Hawks - Season 2 Episode 14 Dark Waters

The Storm Hawks respond to a distress call from the bottom of Terra Aquanos to rescue the Neck Deeps. At the bottom they find monsters which have been released by I.J. Domiwick from a sealed cavern. In this cavern are supposed endless tunnels that lead to everywhere throughout the Atmos, even the fabled "other side". While the Storm Hawks and Neck Deeps try to seal the cavern, Domiwick escapes, but only delays their plan and swims into the cavern before Finn reseals it. However, just as the Storm Hawks head for the surface, one of the monsters punctures the Condor, causing it to flood. All but Aerrow abandon ship, Aerrow having giving his breather to Piper after Domiwick stole hers. Aerrow manages to make it to the surface while riding atop the monster, now called "Bessie", to satisfy Stork's belief that it exists. In the last scene, Domiwick is seen crawling up onto shore on an unknown land.