Wikipedia says:
Controversy was generated concerning the last four minutes of the original music video. Jackson walks out of the studio as a black panther and then morphs into himself.[13] Then he walks outside to perform some of his most physically complicated dance techniques, in a similar way to "Billie Jean". This part contained sexually suggestive scenes when Jackson starts to grab his crotch[12], and then zips his pants up. In the original version, Jackson is seen smashing windows[12], destroying a car and causing an inn (called the "Royal Arms") to explode. Jackson later apologized saying that the violent and suggestive behaviour was an interpretation of the animal instinct of a black panther, and MTV and other music video networks removed the last four minutes from subsequent broadcasts.[13] To make the vandalism more palatable to viewers, racist graffiti was digitally added to the windows that Jackson smashes (reading "KKK Rules", "Nigger Go Home", "Hitler Lives" and "No More Wetbacks").