Visible crew/equipment: When the ACME Chairman explains his scheme to DJ and Kate, a green screen with two figures in front of it is reflected in the ACME Chairman's glasses. (01:11:05)
Factual error: When Brendan Fraser comes out of the Louvre, the Eiffel Tower is right in front of it. The Louvre and the Eiffel Tower are miles away from each other.
Continuity mistake: When Yosemite Sam is chasing everyone through Las Vegas he drives the race car through a souvenir stand. This puts a large dent in the front hood of the car. This dent disappears when the car is shown next.
Continuity mistake: Brendan Fraser closes Daffy's beak in the car window as they are leaving the garage. When they pull out of the garage and Daffy is back in the car the window is all the way open again.
Continuity mistake: Bugs Bunny shows his displeasure with Marvin Martian by keying the Martian Maggot. Later when Bugs Bunny pulls the "Lost Tourist" joke (and wins $5.00 from Daffy Duck) the scratch on the Martian Maggot is repaired.
Revealing mistake: When the Chairman is watching the TV screen where Damien Drake is being interrogated, the man steps in front of the screen and says "he's about to crack," then he walks backwards as if being pulled, but you can tell the moment Damien puts his legs around him, after several steps. So what pulled him back?
Continuity mistake: In the opening scene when Brendan Fraser falls on the table, he stands up and it goes flying. There are only empty plates on it, but when it shows the film directors, they are covered in food.
Continuity mistake: When Daffy, Bugs, Kate and Brendan are in the forest, Kate and Brendan have knives, but when they encounter Granny the knives are gone.
Continuity mistake: When DJ and Daffy leave, the car that comes up from the revolving floor is a TVR Tuscan,but when Kate and Bugs,leave for Las Vegas in it, it turns into a Lotus Elise.If you live in Europe, and like cars, this is easy to spot,because the Lotus is and open top car with a flat rear-end, while the TVR is a closed roof car and has a rounder rear-end.
Revealing mistake: Throughout the movie, in Steve Martin's close-ups, you can see the line where his wig is.
Revealing mistake: In Africa, DJ and his group ride with Tweety and Sylvester an obviously Indian elephant (much smaller than the African one).
Continuity mistake: In the scene with DJ and Daffy Duck in DJ's house, Daffy throws an apple at DJ's face and hits him on the cheek. In the next shot, DJ's rubbing his forehead, as though he got hit there.
Revealing mistake: In the scene where the ACME Chairman turns on the screen to show Damien Drake tied up, you can see he has no remote in his hands and is just miming the action.
Continuity mistake: In the shot of Bugs saying, "Hey, what do you know? I found Nemo," he reals a fish out of the water. In the very next shot, the fish vanishes.
Answer: It's the alien from "The Man from Planet X".