The listing, Lot of 4 buffalo nickels 1920 & 1923 two each possible error not restored has ended.
The 1920 in top right is damaged
These are all partial, but readable dates
The 1920 in top left has extra metal behind the front legs, under its stomach.
This could be a major die break, what many people mistakenly call a cud
But as my close up pics show, when the light hits the area at an angle, this metal is a different color. But in hand, at different angles, it's the same color
Idk. I think it's most likely after mint damage. I'm 70/30 that this is NOT an error, but I don't know enough to rule it out. A guess is it's some kind of solder.
So please consider that this is NOT an error when bidding. I don't want to lead anyone astray. But it is an oddity, and maybe you'll get lucky and it is an error. Shrug