C. Caroll was an assistant football coach at Coal Hill Academy. Believing Coach Dawson to be pushing the football team too hard, he entered the changing rooms to talk to him where he was killed by the skin-peeling dragon to feed to the dragon's mate. (TV: The Coach with the Dragon Tattoo)
Behind the scenes
Though Caroll is correct from an in-universe perspective as it is how his surname is notated on the Honour Roll, this spelling is actually the result of an error. The shooting draft of the script  lists the intended spelling with two rs. This intended spelling is also indicated by the credits for The Coach with the Dragon Tattoo, where he is listed as "Assistant Coach Carroll".