5 divers set off to a semi-submerged shipwreck in the shallow waters off the coast of Pensacola, FL on a raft. Most of them, however, would not make it.
When asked what happened and what killed his friends, the lone 16-year old survivor, Brian McCleary, ended up describing the green guy here
The show started airing early January, 1962, in Florida (the state this happened in). The survivor’s sketch bared an uncanny resemblance. Though the survivor didn’t explicitly mention it was Cecil the dragon, it’s still very obvious as to what he was implicating. (Sort of like saying you and your friends were attacked by a yellow mouse-like monster with a lightning bolt for a tail and red cheeks, and then drawing a sketch of Pikachu, without actually mentioning it was Pikachu.)
How would a cartoon character even come to life in the first place? For something to live it needs things like blood, a brain, functional neurons, etc. a drawing on paper doesn’t have that, so where would all those things come from?
Nonetheless, the survivor stuck to his story for the remainder of his life.