Is it just me or did no one talk about this yet on here?
Either way, late last year, a YouTuber under the name of "brian the hedgehog" obtained a pre-production sample cartridge of Michael Jackson's Moonwalker for the SEGA Genesis. The kicker? It has "Thriller"! Whereas the final version has "Another Part of Me" in place of it in the zombie levels, it's obvious it was meant to have Thriller (evidenced by the Thriller Dance still being in the game)
Eventually, while no ROM of the sample has been dumped yet, brian did upload a video that featured the Moonwalker version of the song by itself (He also recorded gameplay videos of the zombie levels in action).
Have a listen.
Some questions still remain, though - Was Thriller also intended to be in the arcade/Master System versions? Is this the farthest Thriller got to be in the game before getting replaced? Are there more copies like this one out there, waiting to be dug up?