Perhaps a better question would be, "What *didn't* happen to Billy Barty". The man, primarily known to us as "Sparky the Firefly", had a long-standing career in Show Business, and spent a considerable amount of time working with Sid and Marty Krofft. His other Krofft works include H.R. Pufnstuf, Sigmund and the Sea Monsters, and Dr. Shrinker.
Although Billy was in his 40s when he worked on the Bugaloos, nobody ever thought Sparky the Firefly was anything but a scared little kid, timid and shy, bumbling and foolish, heartwarming and sincere. He fully personnified the kid inside the costume, and produced a character that couldn't have been a better match for The Bugaloos.
Here's a picture of Billy Barty with a Bugaloos fan named Jennifer, around 1979 or 1980 (when she was about 10).
I was lucky enough to meet Billy Barty at the Krofft Collectibles Auction, in August of 1998. Although he did not remember very much about the Bugaloos, he was glad we enjoyed the show. He was a very warm and friendly man ... he posed for some pictures, signed a few autographs, and got up to personally auction off the "Sparky" costume pieces from the Krofft Road Shows.
On December 23, 2000, Billy Barty passed away due to heart failure, he was 76. His television and film legacy includes over 100 titles, which spanned eight decades, and earned him a star on the Hollywood Walk of Fame. His last appearance may well have been the Sid and Marty Krofft: E! True Hollywood Story, which premiered on December 24th, 2000.
More information on Billy Barty can be found at the following links: