dr. doofenshmirtz appears in both episodes of the spin-off the owca files in which he’s partnered with perry the platypus and had to fight another evil scientist named parenthesis. in the spin-off milo murphy’s law, dr. doofenshmirtz invents time travel and changes his name to professor time. doof also appears in the movie phineas and ferb: candace against the universe where he helps fight the aliens and save earth.