Skilus eel

Skilus eels were carnivorous life-forms native to Surobos. When the Tenth Doctor and his companions were accidentally transported to that world, he had to swim through eel-infested waters in order to retrieve the TARDIS. Jalkis, a native Suroban, aided him by distracting the eels, but was wounded by one of them in the process. (COMIC: Shipwreck!)