Revealing mistake: In the scene when the aliens first enter Valerie's house, Mac and Zeebo find the fish tank and eat one fish each. The shot turns to Valerie's stunned reaction then back to the aliens, who are smiling widely, pleased with their stunt. If you look at Mac's teeth, you can see they are bright white up to his first molar, which is a give-away at his fake white fronts.
Earth Girls Are Easy (1988)
1 revealing mistake - chronological order
Directed by: Julien Temple
Starring: Jim Carrey, Jeff Goldblum, Geena Davis, Damon Wayans
Continuity mistake: In the car, Candy is spraying on hairspray with one hand and her other hand is styling her hair. In the next shot, the previously empty hand, which was styling, now has a pink mirror in it.
Candy: If you wanna be a femme fatale, you can't rest on your L'Oréals.
Valerie: You know, I think she might be right.
Candy: Grab the bleach, she's seen the light.