I vote for a stray spring retainer from your favorite semi-automatic rifle.
More related, a spring retainer from a VW:
https://www.buggiesunlimited.com/golf-cart/e-z-go-3-8andprime;-accelerator-spring-retainer-(fits-1994-up)/6389
And how did the dime escape the carnage or is that the prize for guessing corectly? :-)