It's an old reddit reference. Guy's family kept a knife in the bathroom because they poop too big. He didn't realize that wasn't normal. Or something like that.

The.Poop.Knife.

Poop knife

https://bg3.wiki/wiki/Poo-Scraper

Funny enough, this is the exact reaction of the person from the poop knife story.

It’s an old Reddit story. Some sort of “what quirk does your family have, that you didn’t realize was weird” /r/AskReddit thread.

A dude’s entire family took shits so massive and solid that they had a butter knife that was designated as the poop knife. If they took a shit too big to fit down the drain, they would use the poop knife to dice it up before flushing. Apparently this was a fairly common occurrence, to the point that they just had it hanging on the laundry room wall for anyone to use in any of the bathrooms in the house.

And then he went to a house party, and had to take a shit. So he dropped a football in the host’s toilet, walked out of the bathroom, and casually asked where their poop knife was. Cue a literal record scratch moment, where the music was paused and the entire party turned to go “where is the what?” It was in that moment that the dude realized that normal people don’t have poop knives.

People used to cover their swords or knives in poop/shit so that non leathal scrapes or cuts would be sure to get infected at a time before medicine/antibiotics.

Ignore the prune lobby, folks

The Beastmaster [1982]