One of very few public domain Disney shorts and an uncharacteristically spooky one at that in time for Halloween (though of course most of the films I’ve posted in this thread are quite Halloween appropriate).
The Mad Doctor (1933)
https://www.youtube.com/watch?v=LPW70q4w5pw - from the Laser Time YouTube channel (6 mins long - 720p upscale)
Synopsis:
Mickey must save Pluto from a mad doctor’s lair.
Directed by David Hand.
Cast: Walt Disney, Billy Bletcher & Pinto Colvig.
Trivia:
The short’s horror overtones made it unusual for a Mickey Mouse cartoon. Some theaters refused to show it, believing it to be too scary for kids. At one time, for this reason, it was banned entirely in the United Kingdom, as well as Nazi Germany.