aka The Trollenberg Horror. This could be on youtube or turner classics....

I cannot recall a better Forest Tucker piece of work this side of F troup.

British film with an American star.... Forest Tucker who does an excellent job of impersonating Jeremy Clarkson (no other car related content).

This is a scifi film from my youth. Scary in that the horror is not seen until later. Several people loose their heads on a remote Swiss mountain which has a strange cloud moving around on it. The folks in the town try and pass it off as mountain climbing accidents. The mountain has an institute for study of something built like a bank, includes scientist with accent, and it's fireproof you know....because of avalanches.

Lots of freezing, tram action, Molotov cocktails, possession by monsters, yes...eye monsters that crawl, and Forest Tucker.

Wherever the cloud goes there are strange happenings. Along comes an American who works for some kind of UN organization , he is visiting his scientist friend who tells him of these strange occurrences. Also along for the train ride is a psychic and her sister....strange days indeed. It all seems a bit silly given 1958 special effects, but you just have to see Forest....I cannot watch the film now without thinking of Jeremy. 7.5 outta 10.