There’s also “the ruum” by Arthur Porges[0]. We got as part of English class in high school, a long time ago.

Try not to read the Wikipedia as it might spoil the short story, there’s the pdf available on the web somewhere

[0] https://en.wikipedia.org/wiki/The_Ruum

Yes! I remember reading that, as you say, a long time ago. This is the first time I’ve seen someone else reference it. I love that story.