The Fenris Wolf appears in the episode "Meet Captain America". It was one of the mythical specimens that were captured by Red Skull upon discovering an entrance to Asgard. Due to a control collar around its neck, the wolf was forced to obey Red Skull; after it is released however, it ends up fighting Captain America and Bucky.
The Fenris Wolf appears in the two-part episode "Avenging Spider-Man" as a host for the Venom symbiote among the other Asgardian creatures as part of a takeover conducted by Loki and Doctor Octopus. After Spider-Man switches minds with Loki, the Venom-wolf attacks Spider-Man in Loki's body until it is blasted away by Loki's scepter. It runs into Spider-Man once again (after Spider-Man had returned to own body). This time, Spider-Man was aided by Falcon, so they managed to remove the symbiote from Fenris and shock it into unconsciousness. After Loki is transferred to another realm, the Fenris Wolf, Ulik, and the rest of the Asgardian creatures confront Loki as revenge for Loki controlling them.