So the dude who was the alien in Alien walked off the set after the movie was finished and disafuckinpeared.
“In 1978, Bolaji Badejo, a graphic design student who was spotted in a bar and chosen to play a monster role due to his immense 6”10 height and slender frame, left Shepperton Studios after his last day of shooting and apparently never resurfaced again. Despite playing the titular monster in some of its most pivotal scenes [corridor Alien shots, Lambert/Parker death, Narcissus finale – other stuntmen portrayed the more physical stunts], Badejo features in no Alien retrospective documentary, other than in glimpses of him in archve footage. Unlike Predator creature actor Kevin Peter Hall, Bolaji was not an actor, and has not enjoyed the cult status of the late Hall. Bolaji Badejo has simply disappeared.”
‘Bolaji was about seven feet tall and looked like he came from a different universe anyway, and they made up this Alien suit for him. Ridley was very careful not to have him standing around, drinking tea with us during breaks and because he was kept apart from us and we never chatted, when it came to seeing him as this creature during a scene, it was electrifying. It didn’t feel that we were acting scared at all.’
Sigourney Weaver, Daily Mail interview, 2010.
Follow the link for an article about him
(via Strange Shapes: Under the Skin: Finding Bolaji Badejo)