Wander Over Yonder (2013)

S01E07 The Pet

Wander and Sylvia stumble upon a deserted spaceship, where they come face-to-face with a terrifying alien creature intent on devouring them. Wander affectionately dubs the menacing beast Captain Tim. While Sylvia views the creature as a dangerous adversary, Wander finds himself drawn to the fierce little monster and decides to take on the challenge of training it as his new pet.