In an extended scene at the end of The Day the Earth Stood Still, the pioneering sci-fi film, the robot Gort prepares to punish humankind after the US army shoots down his alien companion Klaatu. Patricia Neal's character races to the spaceship to stop him, where she utters the immortal line "Klaatu barada nikto" before the robot carries her into the spaceship itself. Little did the audience know the physical cost the sequence was having on the actor playing Gort.
Lock Martin, born in 1916, was 7ft 7in tall. There had been a search to find an actor tall enough for the role; various actors were proposed, including Jack Palance. Then someone remembered a tall doorman at Grauman's Chinese Theatre. Until then, Martin had been a nobody, working in short-term jobs.
The Gort costume was a problem; although Martin was tall, he was not strong, and wearing the foam-rubber suit was exhausting. In the scene, he has to carry Neal and the body of Klaatu on to the spaceship up a ramp. The only way to get round his inability to carry either was to use dummies, trick shots and wires.
In the final scene, with Gort in the background and a revived Klaatu on the ramp, Martin is standing where he is because he can't stand on the ramp at all. You can see that painful muscular spasms are making his right arm twitch.
Martin almost certainly had Marfan syndrome, a tissue disorder that creates an elongated form. He had a brief career, and hosted a TV show known as The Gentle Giant. He died in 1959, a few years after performing, uncredited, as the Yeti in The Abominable Snowman of the Himalayas.