Ozzy Osbourne Reveals Halloween Costume ... Creates Huge Mystery (VIDEO)

Ozzy Osbourne gave us a giant clue about what he's cooking up for Halloween, and by giant clue we mean ... he flat out told us -- and we still have ZERO clues about what he'll be wearing this weekend.

Rock's prince of darkness was haunting Beverly Hills when our photog asked what his Halloween plans were, and Ozzy was a total open book.

You've gotta see, and hear, his response. Best we can figure, there's gonna be a "show" and possibly a party in the middle east? Whatever, it's Ozzy ... it'll be awesome.