What is this mark?

I found this 1959 D penny with a Q mark above liberty. Is this an intentional thing by someone or is this an error? I posted obverse and reverse.

 

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Someone just stamped it, nothing like that could happen at the mint.

 

I agree, someone intentionally stamped it - to me, it looks like a putting green with flag - perhaps someone got cute making ball markers (for golf)? People do crazy things to coins!

 

Whenever you see any mark incused into the field it is usually post mint damage.

 

Counter stamp. PMD (Post Mint Damage). Welcome to CT.

 

I believe the Q is for Edward Spring of New York. It's a counterstamp as previously mentioned and it's considered damaged. However, there are a large number of collectors of this sort of thing.
Due to the green gunk it's worth about a quarter. Welcome to CT.

 

It is a cent made at "Q" branch at MI6. It is very likely one of James Bond's coins.