My opinion. a Rolling Dryer coin removed before it got TOO bad. on a rolling coin, the diameter gets smaller and the rim gets taller as the machine spins the longer it's in there the worse it gets. on a tumbling coin the edge rim wears down instead. Below is the basic theory of what's going on although nobody has really seen it as it happens, just the results when you service them to remove the jam or get them spinning again. they are pulled out of laundromat machines during repairs and services quite frequently looking like that or worse and it's the top loading dryers usually, not the front loaders if a coin get in there on a front loader it eventually lays flat at the bottom until enough pile up to jam it up and stop it spinning.
I am not familiar with dryer coins however it certainly appears that could fit the description. When I see these I am reminded of coin spooning which was an activity I participated in as a lad. Tap the edges of a coin long enough and the edge rolls up. I would do it with nickels and drill out the center to create a ring myself.
Agree with @John Burgess Its a dryer coin @Randy Abercrombie www.error-ref.com has a nice explanation and pic of dryer coins
