Looks like it was hit with something a few times to flatten out the image there. The damage on that side of the back is why I think so... but we'll see if anyone agrees with me
It's a multi-level cud. The shape of the fracture zone can vary enormously from vertical, to sloping, to stepped. Yours falls into the last category.
khay- The reverse is weakly struck in the area directly opposite the cud. The roughness you see in that area of the reverse is the original unstruck planchet surface. TTuck- Where did you find this coin?
In pocket change. I have it on Ebay right now if you are interested in it. The bid is at $25 right now. http://www.ebay.com/itm/110807727782?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649
With the amount of nicks and wear from circulation, I can't help but think this happened post mint. I can't see this not getting snagged up by some one almost immediately after being released into circulation. But, I will not doubt a good explanation contradicting my opinion.
If Mike Diamond says it's an error, it's an error. It would be really difficult to reproduce that kind of cud after striking. It's a nice specimen, given the strike I'll speculate this is a mid 80's nickel.
If you look closely at the area in qyuestion on the obverse, you will see that the upset rim is intact and as a result of the break in the obverse, the reverse die graduates from normal strike to almost no strike in the immediate area of the "blob" on the obverse. Additionally, in order to flatten the image on the reverse, you would see a distortion of the rim making it out of round. In my opinion, this is a stepped cud, not a pmd
A featureless, often puckered area is always present opposite a large cud. That's for two reasons; 1) A lack of resistance to the impact of the intact die opposite the void in the opposite die, and 2) a tendency for coin metal to bulge and buckle into the void. This coin is undamaged and appears to be in uncirculated or AU condition.
If Mark says, Gbroke says, Merc crazy says, Mike Diamond says its an error, then its an error. Then its an error