Donald Duck: Duck Pimples (1945)

Though this isn't a Halloween cartoon, I think it has a creepy atmosphere to it!

The Three Stooges: If a Body Meets a Body (1945)

Originally released on August 30, 1945, this is one of the last Three Stooges shorts to feature Curly. It is basically a remake of "The Laurel-Hardy Murder Case" (1930). Laurel and Hardy's short and the Stooges' short both used Fred Kelsey in the role of the detective.