Coal Black and de Sebben Dwarfs [wiki] was directed by Bob Clampett and released in 1943 by Warner Bros Pictures under the Merrie Melodies series. The animation is an all-black parody of the Brothers Grimm fairy tale (and Disney cartoon) Snow White.
Needless to say, Coal Black and de Sebben Dwarfs is one very controversial cartoon. It is replete with racist imagery combined with "hot jazz mentality" (whatever that means) and sexual overtones.
Despite being banned, this cartoon is often included in the list of greatest animated films ever made and is considered Clampett's best masterpiece.
Every time I see it, I am reminded of Song of the South, which is also an important piece of history, but has never been released on video in the US. Disney appears content to let this film slip into obscurity.
http://en.wikipedia.org/wiki/Song_of_the_South