exists for no clear reason

Sounds like Humans

It also only has one hole, which, if you ask some topologists, is what humans have.
I thought most humans are 7 holes

Mouth, Anus, Nasal Passages (2), Occular passages (2), Aural passages (2) = 8. -1 for topology reasons (one “hole” is a divot, not a tube, and a divot is topologically equivalent to a smooth surface) = 7.

Math checks out. (And I think stand-up maths or some other maths youtuber did a longer version of this post with more detailed and complete reasoning.)

I would post the human floss video. But it seems to be lost media. It was of a guy who got extra strength floss, tied it to one of his teeth, and one end to a pen lid… Swallowed the entire roll. Found the lid days later, and then pulled it back and forth, to floss himself. The video would be +10 years old.

Seems dangerous. There are sections where you wouldn’t want the floss pulled taut, and certainly not the whole thing.

I wonder if it was just a magic / fx video; at least the “to floss himself” bit.

I just remembered the name. But searching it up just gives reddit posts with dead links. It was called “full body floss.” All the the youtube links are dead. But I wouldn’t recommend trying to do.