The Amazing World of Gumball (2011)

S6E43 The BFFs

Gumball's childhood friend Fuzzy unexpectedly shows up at his door, leaving Darwin feeling insecure about his place in Gumball's life. As he grapples with the fact that Gumball once had a best friend before him, Darwin's jealousy begins to bubble to the surface, making it difficult for him to hide his feelings.