i get this nickel with a punch coins from e bay i be leave it is a doubled die on both the reverse and obverse at least my opinion i could be wrong i still in the first grade of coin collecting here a scan of both sides
agree with above - die deterioration from a worn or overused die. Very very very common - not an error, I'm sorry to say
This is a classic case of die deterioration doubling. It is *extremely* common on 1999 nickels. See more here: https://en.wikipedia.org/wiki/Die-deterioration_doubling http://www.error-ref.com/die-deterioration-doubling-raised/
I have that one too the 1999 P, Five cents ,The repunchment mark is visible, in fact i have 4 coins with all doubled die With full steps and I know it is worth more than the face value and i tried to watch on YouTube to find out How much!
The 99 P if doubled is a form of worthless doubling. Especially if the MM is doubled. The RPM ended in 1989 when the mm was no longer hand punched into the working dies.