(Dr. XXX)
This evil scientist with a deep loud voice who rolls his R's appears in the short "The Mad Doctor" (January 21, 1933 ). In this cartoon, he kidnaps Pluto and wants to graft his head onto a hen's body :
He lives in a castle with bats and living skelettons (there is even a spider-skeleton) , and his real last name is XXX :
Mickey will come to save his dog, but he will finally be taken as a new victim by the Doctor, before waking up and realizing all this was just a dream...
In "Mickey Mania : The Timeless Adventures of Mickey Mouse", a videogame by Sony Imagesoft from1994, Mickey visits some cartoons he appeared in in chronological order : "Steamboat Willie", "The Band Concert", "Moose Hunters", "Lonesome Ghosts", "Mickey and the Beanstalk", "The Prince and the Pauper", and of course "The Mad Doctor". I have a poster of the pocket of the game, on which we can see the Mad Doctor, a little bit modernized :
