A monkey’s paw is a talisman that grants wishes but the wishes are usually granted in a way not expected by the requester, usually as a punishment for tampering with fate.

Here, the guy requests “make me a sandwich”, the monkey’s paw would grant the wish by literally interpreting the wish.

If you want to see more, there is a subreddit called /r/monkeyspaw. Not sure if there’s a community on Lemmy.