Dark Danny is the evil full-ghost version of Danny Phantom, created by the joining of the ghost-halves of the show's protagonist and the show's antagonist, Vlad Plasmius. Dark Danny is considered one of most dangerous and powerful enemies Danny has had to face.
Dark Danny is in Halloween Town where he has kicked Oogie Boogie out of his manor. Dark Danny is a rival to both Jack Skellington and Samurai Jack. Dark Danny has the Skull of the Undead, which he has protected with a Ghost Shield. It is suspected that Dark Danny is behind the appearance of numerous ghosts and monsters in both Amity Park and Townsville; it is believed that the Fusion monsters infesting Endsville and Eternal Meadows are Halloween Town creatures that have been infused with Fusion Matter. Danny Phantom, with the aid of Providence, is trying to capture Dark Danny and bring him under control.
Dark Danny is the leader of the Skull Team.
- Dark Danny once killed Drigona.
- Butch Hartman realized the worst enemy Danny Phantom could fight would be an evil version of himself, so he decided to mix in time-travel to allow Danny to battle a purely evil ghost self. Dark Danny was not originally revealed in the advertisements for "The Ultimate Enemy" on Nickelodeon to preserve the shock factor of Danny's future self being his own worst enemy. Dark Danny had been intended to return after "The Ultimate Alien"; however, due to Danny Phantom's cancellation, this never occurred.