Yellow Thing On The Back
When someone got a new pen, they were confused to see this thing on the other end of it. Despite trying it, they said it definitely wasn’t an eraser. They said that the identifying characteristics it had included having a waxy consistency.
The internet knew exactly what this was: a gel highlighter. They also noted that it likely didn’t mark on the paper when trying to erase because it’s either old or it’s just that gel highlighters don’t work that well.