Crayon Boy is one of the three secondary villains in animated television horror film Scooby-Doo: The Watcher in the Barn and a member of a biker gang. He is voiced by Richard Steven Horvitz, who also voiced Dag the Beaver in 1997 animated television series Angry Beavers and Rodney the Squirrel in 2006 animated television series Squirrel Boy. His real name was unknown.
Crayon Boy, along with two bikers Rose Wilson (Pamela Adlon) and Black Knight (Jennifer Hale), travels to Ponyville and stops in a small convenience store. In the store, Crayon Boy takes to hassling customer named Hoagie Gilligan (Benjamin Diskin), having both Rose and Black Knight restrain Hoagie's Japanese American friend named Kuki Sanban (Lauren Tom). Having grabbed Kuki's green wallet when she attempted to throw it to Hoagie, Crayom Boy taunts Hoagie, making Hoagie grudgingly ask for it back as address him as "sir".
After Kuki mangles their motorcycles as revenge for troubling her and Hoagie, Crayon Boy and his fellow bikers follow both Kuki and Hoagie back to Sweet Apple Acres. Despite being reluctant in participate in his friends' plan to burn down the Sweet Apple Acres barn after siphoning gas from Applejack's orange Volkswagen bus, Crayon Boy, after being reassured by Rose that nobody will get killed or hurt, wanders off to look around. Going into the barn, Crayon Boy nonchalantly begins toying with some of the barn equipment lying around, eventually climbing up onto the second floor. Finding a rope and pulley used to hoist hay, Crayon Boy begins swinging from it for fun. Her compatriot Black Knight sees this and tells Crayon Boy to stop fooling around like an idiot by demanding him to come down so they can help Rose in her revenge plans. Unseen by Black Knight, Crayon Boy was ultimately grabbed by Fauntleroy Donaldson and pulled back into the barn, where Fauntleroy impales him to a barn rafter by the throat with a sharp pitchfork. Shortly, before Fauntleroy kills her too, Black Knight found Crayon Boy's corpse, which Fauntleroy later moves. Crayon Boy's corpse, along with the corpses of Rose and Black Knight were found by the authorities and taken away by the paramedics.
- In the original Scooby-Doo novel, Crayon Boy is a minor villain that doesn't appear until page 209.