The story is about a man who comes to a hotel as part of his travels. He has stayed there before and even notices that the man at the front desk is acting in a more formal fashion to him than usual. The traveler requests a specific room that has a water stain on the wallpaper that is shaped like a joker or a jester. I think the name of the short story may even be "The Joker" or something similar. He knows that there is something paranormal about the stain and wants to take the opportunity to learn more about it. The traveler moves the tv in front of the stain and wakes up later to see that the stain has moved to a different spot on the wall so it is no longer hidden behind the tv.
The story ends with
The man's consciousness gets sucked into the stain and some force from the stain takes over his body. The man is observing this as if he is looking out from the wall. I think he can tell that there are others in that place with him and even suspects that this may be the reason that the man at the front desk was acting strangely.
I thought it was a Stephen King story but I might just have been confusing it with his short story 1408. I know that I read it in a book that was a collection of short fantasy/horror stories, possibly a year's end collection. This could have been an older story as I don't recall any modern technology in the story itself and it certainly was at least 5 years ago that I read it.
I am looking for the name of the author and the story and if possible, the name of the collection it appeared in.