This science fiction short story is about a team of astronauts/space explorers who land on an alien planet. An alien entity, that exists in a gaseous state, is lurking at the bottom of a well or hole. It briefly inhabits the body of each astronaut it encounters, seeing from their POV and causing them to go crazy/die/kill the others. When one man dies the entity jumps into the body/mind of another.
The story is narrated by the alien entity, and everything is from its point of view. It overhears the astronauts' conversations as they try to figure out what is happening.
It is a stand-alone short story (maybe 6 or 7 pages), and it is not part of a larger novel.
I have a feeling this may be one of Ray Bradbury's later short stories (but I could be wrong). I must have encountered this story in an anthology of relatively well-known scifi stories. I read it around 2007, but the story is probably from the 1960s/1970s.