Visible crew/equipment: During the party, Deb and Hilly join Gary and Wyatt in the bathroom, and when the boys step into the shower enclosure and close the glass door, a crewmember's moving reflection is visible on the shower head.
Weird Science (1985)
1 visible crew/equipment mistake - chronological order
Directed by: John Hughes
Starring: Bill Paxton, Anthony Michael Hall, Kelly LeBrock, Ilan Mitchell-Smith
Revealing mistake: When Gary and Wyatt come home and see Chet turned into a pile of poo, Chet shoots his tongue from his mouth and catches a fly. Look closely, the tongue flies completely out of his mouth and is attached to a metal spring. (01:24:55)
Trivia: The town in which Gary and Wyatt live is called Shermer. Another John Hughes reference to The Breakfast Club and Ferris Bueller's Day Off. (00:11:35 - 00:16:50)
More questions & answers from Weird Science
Answer: According to the Wikipedia page for this movie, Lisa transforms Chet into a giant, talking turd.
Casual Person