The horror trope that scares me the most

I don’t know what it’s called but it stems from when i was a kid in that episode of SpongeBob, where he breaks his butt and he doesn’t want to leave the house so Patrick dresses up in the gorilla suit and when SpongeBob calls him out, a second Patrick shows up and the question is “if Patrick is really in the gorilla suit then who’s the other Patrick?” I still get the heebie-jeebies when I watch that episode.

A recent adult example is from the book We Used to Live Here where spoiler the main character is in a hotel room with her girlfriend and then suddenly gets a call at 3 o’clock in the morning from her girlfriend

I made light of it, but when I glanced down at my phone during dinner with my boyfriend, I could’ve sworn it said he was calling me and we joked about this specific fear that I have and how I would’ve handled it

does this trope have a specific name? even though it freaks me out so much I would like to find more movies and books that have this. 😭