The Man from Planet X is a 1951 independently made American black-and-white science fiction horror film, produced by Jack Pollexfen and Aubrey Wisberg, directed by Edgar G. Ulmer, that stars Robert Clarke, Margaret Field, and William Schallert. The story concerns a humanoid who lands on Earth in a spaceship from a mysterious planet and makes contact with a small group of humans on an isolated, fog-shrouded Scottish moor.
https://en.wikipedia.org/wiki/The_Man_from_Planet_X
And here's a short description of this film from director Joe Dante.
https://youtu.be/IEz-4H2tcu8