Savage syndrome 

Named after Fred Savage, formerly of The Wonder Years. It is the condition where a child widely regarded as cute or attractive morphs into a hideous beastly creature after puberty. Savage syndrome is often applied to child stars, however has become equally common in reference to "everyday folk". Although this condition existed prior to the 1990's, Fred Savage's fame and degree of disability warranted the disorder being named in his honor. (Think amyotrophic lateral sclerosis and Lou Gherig’s disease.)

Good God!!! Looks like Peter Billingsley got Savage syndrome.

Savage syndrome by Kimberlee July 1, 2005

Fred Savage Syndrome 

When your freakin adorable as a kid and ugly as fuck when you grow up

Woman at grocery store: "Oh my god, you make the most beautiful babies!"
Me: "Thanks! I just hope they don't get Fred Savage Syndrome."

Fred Savage Syndrome by I'm Bad Ass March 13, 2014