It’s a suction cup. Looks like this: https://duckduckgo.com/?q=suction+cup+darts&iax=1&ia=images
“Easton spoke with The Guardian about a sneezing fit that he endured recently that dislodged the sucker of a toy dart from his nasal cavity, the very same sucker he’d shoved up his nose as a seven-year-old. The sucker, which was the size of a “penny coin,” had been lodged up there for nearly his whole life until he sneezed it out onto his computer at his home in Surrey, England.”