The Skeletons are characters that first appeared in one of the classic Silly Symphonies, in which being The Skeleton Dance, which was released in 1929. The skeletons have been long associated with the macabre side of Disney.
The Skeletons have made numerous other appearances in other cartoons such as The Haunted House and The Mad Doctor.
In Epic Mickey series
The Skeletons reappear residing in the Wasteland in Lonesome Manor (Wasteland's version of the Haunted Mansion) and appearing in most of its Projector Screens, including the Mad Doctor and Haunted House projector screens.
In the sequel, the Skeletons return and appear in all of the Skeleton Dance projector screens, where you will need to be careful as they dance around. Their cartoon is one of the unlockables on the main menu.