General This UK-based short story was from a horror or SciFi compilation I read during the late 80s/early 90s (but was almost definitely from earlier). I have a feeling the compilation was probably aimed at early teens as I'd likely have found it in the school library.
Plot The story was based around a child visiting a house on a residential street. They're greeted by an elderly resident who invites them inside where the general sense of unease grows.
I believe it becomes apparent that the frail resident (who has been walking around the house steadying themselves against the wall), is actually connected and 'as one' with the wall, and that everything - the resident, the house, all the furniture inside etc is just one continuous entity which intends to trap and devour the child. There's a very vivid description of the wall becoming 'fleshy' and rippling behind the touch of the person's hand which is where it becomes apparent they are seamless.
The child escapes and runs to a public payphone to call for the police. His final thought before he's digested by the phonebox is hearing the voice of the 'house alien' introducing the phonebox as another one of the species. He starts to notice the phone cord and receiver he holds in his hand begins to look more tentacle-like and the windows more opaque and pink.