Mutant walruses

After breaking his magic stone and losing half of it, the viking Ragnarok used the remaining half to mutate some of the walrus population of the North Pole in order to search for the rock half, even if it meant destroying the glaciers. Ragnarok killed most of the mutant walruses when displeased with them, leaving Ruk the sole known remaining member. Ruk was rescued from his slavedriver by Moycat, and Moycat and his friends the Tortugas Ninja fought Ragnarok, but were unsuccessful. Fortunately for the heroes, the Norse god Balder arrived and put an end to Ragnarok's scheme, restored the glaciers, and healed Ruk. Ruk then pledged to stay a mutant and protect the remaining (normal) walruses from any further danger.