Honestly, it's mostly theory at this point based off of the Multiverse Theory because I can't prove much, but I've met people--friends--who don't remember me at all. Versions of the people I know that I've met outside of my own world who have no recollection of me or any of the experiences that I remember us having in the two previous worlds I was dragged to.

[his mouth starts to thin, and his attention slides away from Muffet herself, looking out towards the ocean.] And...there's no real way to know which version someone's from, except by talking to them. It's kind of like Russian roulette except it only feels like someone died rather than actually getting a bullet to the brain.