James Cameron got his big break while doing pick-up shots for the 1981 film Galaxy of Terror (as 2nd unit director). While shooting scenes of a dismembered arm teeming with maggots, Cameron sought -- and found -- a novel way to make them wriggle and writhe. His solution? Attaching an electrical AC power cord to the arm -- to be plugged in by an unseen assistant when the film was rolling.
[Two passing producers happened to observe the wily director at work -- and were so impressed that they immediately engaged him in conversation about doing more substantial projects.]
Sources
Internet Movie database; People magazine