Boasting peafowl, Uncommon 2/2/2
Legend
N=your keywords - enemy keywords
M=your nonzero - enemy zero cost
Enemy stock -N
Stock +M
That's a lot of math, but it's certainly unique.
My first thought is that this would be the easiest Legend to play being 2/2/2 Uncommon. Decks that draw Rares with ease would use this just for the keyword effect without bothering to optimize the written effect.
My second thought is that I hope M and N can be negative values rather than setting a lower bounds of zero. If you can play this card at a time that it reduces your stock or benefits your opponent, if not both, then I have less of an issue with it being a cheap Legend. (Though since it's likely to give you 6 stock after subtracting cost in addition to whatever change it's making to the opponent's stock, this thing could be way out of line.)