The Black Widow Shark is a monstrous cross between a black widow spider and a shark that lurks in the River of Despair, attacking anyone who tries to cross. When the quest for the Time Capsule leads Lion-O, the Thunderkittens and Snarf to the river, the creature lunges at them with snapping jaws, and they barely escape its teeth before crossing the Bridge of Light raised by the Unicorns. A Black Widow Shark surfaces again in Turmagar the Tuska, this time in open ocean on the Tuskas' sea route rather than the River of Despair. Cheetara's reaction on spotting it implies it is the very same beast.
