I think this card is quite UP. Maybe N=double the number of the poison counters?
I was thinking that too, particularly when making that table a few pages back. It's max power is only slightly higher than the max HP, doubling the damage output would make it severely OP, the max possible damage for the current versions are: 20 something for unupped and 30 something for upped. that'd make a card that does 60 damage (upped version).