Alien Ant Farm is a metal band whose breakthrough hit was "Smooth Criminal", a Michael Jackson cover. In the radio version you can clearly hear the samples of Michael's yells. Their bassist does the Jackson vocals when they perform the song live.
Headed by singer-songwriter Dryden Mitchell, with guitaurist Terry Corson, bassist Tye Zamora, and drummer Mike Cosgrove.
Personally, I was unimpressed with the rest of ANThology. Perhaps because "Smooth Criminal" is such a great track, the rest of the album seemed dull in comparison. Of course, I only listend to part of each track in Borders...
The cover (rerecording another artist's work) is a long-standing tradition in modern (twentieth-century) music. Permission granted and properly credited, there's nothing wrong with a cover.