User blog comment:PossesedChipmunk18/How did Darwin become a Talking Fish?/@comment-4060139-20130712211731

All we know so far is that one day (when Gumball was about 2-4 years as shown in The Hero), he sprouted legs and gained the ability to talk and eat food other than fish flakes. His name hints at evolution, but it could be wackier than a simple evolution in the traditional, Darwinist sense. There could be lots of sci-fi wrapped up in it, like a forced evolutionary virus or CHEMICAL X lol.