I saw this coin on Facebook, and the owner was wondering why it looks like this. My thought about the reverse was indirect design transfer and some grease strike-through, but the obverse is very flat, also possibly because of the result of grease. The owner says he pulled it out of a OBW roll. Some other individuals are vehemently saying that this could be done with a vice job, while others think that it could happen at the mint. If it was a vice job, there are lots of things missing (incuse details/lettering from secondary coin, crushed rims, etc.). These are the pictures I have, so sorry that they are not the best. And doing some research revealed a phenomenon called a “greasy ghost”.
Possibly a Greasy Ghost as stated. Also could be.. A Weak Strike which I have seen on another 1955 Cents. There were several 1955 Weak Strikes.
I am also thinking a greasy ghost. I can't see it being the result of a vice job. It looks like it left the mint that way.
Definitely looks like extra grease flowing through the indirect die transfer on the reverse. The obverse has me confused because it looks like PMD. Edit: could be the poor photos and be grease too.
Just a grease filled reverse die. The lack of sufficient striking pressure caused the obverse design to not fully fill the die giving the portrait an odd look. It's a really cool coin in that grade!