bullet or button?

[joekool]

kinda looks like a bullet that exploded, have no clue

 

[connkuku]

take better pictures then somebody might actually be able to even identify that you are holding something...

 

[edjcox]

I think its a "dark blur" Seems they are commonly found but never really identifed as they are elusive to the eye.....

 

[Dodqe]

Looks to me to be the remnants or a button from a pair of denim jeans. The front button part is corroded away and that is the stem and backing...