>>94435711In the Big Picture Show, they scrapped the idea of showing that. Instead, there was another scene (scrapped also), during the campfire at that national park, where Double D would take off his hat in front of Ed n Eddy to show how comfortable he is showing it to them, and they wouldn't make fun of it like they did earlier at the S.S. Almost A Chicken Duck boat.
Along with that, a newspaper clipping would fall out of Double D's hat, showing a much younger Double D in handcuffs in front of a school, formally apologizing. Edd would explain that during a game of dodgeball way back when, Double D suffered too many blows to the head, and he built a Dodgeball Shooting machine that violently attacked the other kids. After that incident, Edd's parents moved away to Peach Creek, and that's when Edd met Ed and Eddy, at the Bottomwess Ed scam.
With that said, I believe that those "blows to the head" left seriously horrid scars, which not only look grotesque, but also remind Double D of that Dodgeball Incident, which is why he's so intent on hiding it not just from others, but from himself as well. That's why he's always covering his head, even when alone.
Not only that, but it's due to that psychologically scarring event that Double D detests the idea of violence, specifically committing violent acts himself, becoming such a somewhat-shy and cowardly pacifist with almost no backbone.
This connects directly to "A Fistful of Ed", and why Double D was so intensely broken by how everyone treated him like a bully.
In the movie, Double D finally grows a backbone after suffering one-to-many scams gone wrong, along with Ed and Eddy (mostly Eddy) playing so many pranks on him, with that fake death that played with his emotions too much. Then later on, he stands up to Eddy's Brother.
