Started doing a little research on the whole ownership of creative property . The Star Wars dude asked if I'd do some concept art for a movie he is pitching to some "Hollywood Execs." Riiiight. Anyway, I humored him and said I was interested just to make sure I'd get the stupid stormtrooper helmet. It sounds like anything I'd create for this guy would become his property but I could retain rights to any original art. I THINK that means that if that guy wanted to take that Star Wars drawing I did, mass produce it, and sell it, he could do it without me seeing a single penny. I could only take the original drawing and sell that if I wanted. It's a shitty deal for an artist, particularly if you design something like the Terminator endoskeleton for a movie studio, the movie goes on to spawn sequels, merchandise, comic series and you never see another cent more than your original fee.
In this case, the guy hasn't offered anything yet - just asked if I was interested. In all likelihood, it'd prob. be for another homemade movie prop. Sounds like a lot of work for little reward. If the guy asks for a design for a cryogenics technician without much more description, the artist is doing all the work: costume design, chracter physical attributes, etc. Not sure it's worth it, other than the slim chance of having something you design get put into a movie.