For the fantasy cult classic Labyrinth, David Bowie played Jareth, the codpiece-sporting Goblin King. And throughout the film, Jareth is constantly twirling crystal balls just to show off how flamboyantly magical he is.
The thing is, Bowie was never spinning those crystal balls. No, director Jim Henson had juggler Michael Moschen secreted away under Bowie's armpit, manipulating those mystical orbs completely blind. I am astounded by how amazing and awkward it would be to spend take after take hanging out under The Thin White Duke's underarms.
BONUS #1 - More Henson Awesomeness: Jim Henson improvising on the set of The Muppet Movie with Frank Oz and his earlier, trippier work.