DoodleBob is a poorly drawn, alter-ego version of SpongeBob. But instead of being good like SpongeBob, he is evil and will do anything to stop his arch enemy SpongeBob SquarePants. He was created by a Magical Pencil, which is even why he was given life. He first appears in the season 2 episode "Frakendoodle" as the main antagonist. SpongeBob intended to use him to play a harmless prank on Squidward, only for DoodleBob to start beating him, swipe the magic pencil, and run away crazily, screaming gibberish. SpongeBob and Patrick chased him to where he had taken residence in a crudely drawn version of SpongeBob's Pineapple house, and when they cornered him SpongeBob erased DoodleBob with the magic pencil. However, unknown to both SpongeBob and Patrick, SpongeBob missed one of DoodleBob's arms.
The arm infiltrated SpongeBob's house that night and then used the magic pencil to restore himself (and also adds a pair of evil eyebrows) before attacking SpongeBob. During a chase, he erases a portion of Spongebob and his house. As the DoodleBob corners SpongeBob, he erases a portion of him (as possible payback) and plus mocks him, provoking SpongeBob. SpongeBob and DoodleBob then struggle with the pencil and cause it to break in half; SpongeBob restores himself, and DoodleBob sharpens his piece of the pencil (though SpongeBob accidentally flings his part of the pencil away through a window at Squidward's house). DoodleBob corners SpongeBob once more, but when he is about to capture SpongeBob and literally erase him from existence, he gets stuck on a piece of paper and SpongeBob realizes this, then captures him in an empty book.
He also appears in SpongeBob SquarePants: Drawn to Life as the main antagonist.
DoodleBob is one of the first antagonists who isn't Plankton on the show.