Teen Titans (2003)

S2E2 Every Dog Has His Day

Feeling neglected by his preoccupied teammates, Beast Boy decides to explore the town, eventually transforming into a green dog. To his astonishment, he bumps into another green dog that is being chased by a flying saucer. In a twist of fate, the saucer mistakenly abducts Beast Boy instead, and its pilot showers him with far more attention than he bargained for.