The Seriously Strange World Of Gumball S01 E02 The Doppelgänger

"fan series"

A new student arrives at Elmore Junior High who looks, speaks, and acts exactly like Gumball—but "better." As Darwin and the family slowly start preferring the "New Gumball," the original Gumball must prove he's the real deal by being as chaotic and disappointing as possible.