The Neville Effect

The phenomenon whereby an awkward, unattractive, often pudgy-looking child grows up to be unbelievably hot.

The first observed case of The Neville Effect, and therefore the boy after whom the effect is named, Neville Longbottom (from the extraordinary Harry Potter series) is the typical example of this phenomenon. He looks a bit awkward and chubby when he is younger, but in a miraculous series of events, grows up to become a badass sex god. Other notable cases include Josh from Drake and Josh.