The Castle Rock theme in Rayman Legends is an arrangement of "Castle Rock" by Michael Jackson, which was originally composed for the game Sonic the Hedgehog 3 but went unused. Rayman Legends incorporates this track into the game's "Castle Rock" level, providing players with a unique and nostalgic musical experience. The collaboration between Michael Jackson and the Sonic the Hedgehog franchise adds an interesting layer of history to the soundtrack of Rayman Legends.