The Day the Earth Stood Still (1951)

Revealing mistake: When Gort goes behind the wall to pick up Patricia Neal, the camera moves about an inch in the same shot, because they had to stop filming, go rig the wires up to Patricia, then start filming once again. (01:17:00)

Hamster

Reporter: I suppose you are just as scared as the rest of us.
Klaatu: In a different way, perhaps. I am fearful when I see people substituting fear for reason.

Trivia: In order to make Gort's body appear seamless, two different costumes were created, one that opened in the back for front shots and one that opened in the front for rear shots. Unfortunately, as someone has already pointed out on this site, it was sometimes rather difficult to co-ordinate which suit was needed for which shot and thus there are several times in the film where Gort's seams can be seen.