Continuity mistake: During the scene when Trevor comes home and listens to the messages on his answering machine, there are 4 messages from Sean's Mom. As Trevor is running around trying to clean up, he's listening to the messages. Only 3 messages are played and when the phone rings it says there are 0 messages.
Continuity mistake: When Trevor and Sean are getting in the mini cart you can see the cart tracks along the side of the mini cart, but in the next shot the tracks change sides.
Factual error: When Sean is crossing the chasm by jumping on the 'magnetic rocks', he jumps onto the edge of several of the rocks. Assuming that the rocks could actually float in the magnetic field as shown, standing on the edge of one of them would cause it to immediately flip.
Continuity mistake: When the movie begins, Trevor enters the lab and his pal is holding the frozen object with his left hand. Half a second later he holds it with the opposite hand.
Continuity mistake: During the scene where Trevor is told that the funds for research have ended, he crosses his arms, then the angle changes and the arms are at rest and he crosses them again.
Answer: A mountain.