Rescue at Midnight Castle

Run time: 22 minutes

"The very first MLP cartoon originally aired on television in 1984, under the simple name of 'My Little Pony', presumably due to Hasbro not planning upon MLP making future TV appearances. In 1986, it aired as part of the My Little Pony and Friends TV series, this time under the name of 'Rescue at Midnight Castle' but a scene including the ‘Little Piece of Rainbow’ song had been edited out. Finally, the special was released as 'Firefly's Adventure' along with a special edition of Firefly.

"It was also released on VHS tape in the UK as "My Little Pony in Dreamland".”

—mylittlewiki.org