- "The Club": Darwin mentions it when he considers covering Colin and Felix, Bobert and Ocho in honey and dropping them in a bear cage.
- "The Boombox": Gumball asks Darwin if he really wanted to help him steal a crocodile from the zoo for Grobblefest.
- "The Roots": It is mentioned in passing.
- "The Faith": Alan is revealed to have volunteered there until he lost his faith in the world, and his absence drives the animals in the zoo crazy. It is unknown if he resumed his position there after this episode.