Dr. XXX is the title character and main antagonist in the 1933 Mickey Mouse short The Mad Doctor. He wants to attach Pluto's head to the body of a chicken in order to "find out if the end result will bark or crow or cackle."
In the original cartoon, Mickey hears Pluto yelping for help in the middle of a stormy night. He looks out the window to find that Pluto is being kidnapped by a man in a black cloak. Mickey follows them to a castle. Unfortunately, Mickey loses them and travels through the mysterious castle to save Pluto. While Mickey is searching, the man in the cloak reveals himself to be a mad scientist to Pluto. He also shows his plan to attach Pluto's head to the body of a chicken to see if it will bark, crow, or cackle, through song. Soon enough, Mickey arrives but is strapped down and captured. The Mad Doctor decides to eliminate Mickey by experimenting on him. Just when Mickey is about to meet his demise, he awakens in his bedroom. It turns out, that it was all a nightmare.
| Mickey Mouse Villains: Pete, Mortimer Mouse, The Phantom Blot, Willie the Giant, Trudy Van Tubb, Butch the Bulldog, Sylvester Shyster, Dr. XXX, Gustav the Giant, Prince Penguin, Lonesome Ghosts (characters), Julius, Dangerous Dan and Idgit the Midget, Yeti, Bitter Flower, The Phantom Blot's nephews
Donald Duck/Scrooge McDuck/DuckTales Villains: Flintheart Glomgold, Magica De Spell, The Beagle Boys, Grandpa Beagle, Ma Beagle, Granny Beagle, Emil Eagle, Argus McSwine, Cinnamon Teal, Lawyer Sharky, Azure Blue, Ben Buzzard, John D. Rockerduck, Spectrus, Merlock, Ottoperotto, The Beagle Babes, Beagle Brats, Volcano's Head, Mark Beaks