@ Frowns N1 you have a genius concept imo.
Could definitely work, though dare I say a tiny bit OP? After all, It's a straight 8/2 2* with an ability which is likely to be useful as often than not... Making it 8/1, or the ability Poison 2 Max 10 would cause it to be very nicely balanced.
Here's my attempt...
7/4 Ability: Backlash: Poison 2, Min 6
Bio: Ever since the curse of the werewolf Russell the Rescue
clan have resolved to do something about the spate of vicious wolf-bites they have treated recently. So, they have employed the werewolf hunter Remus Greycloak, to slay Russell to end the monthly madness. Remus also knows how to use the poisonous herb Belladonna to heal those Russell infects with lycanthropy, though this itself is very risky...
Notes: a powerful 7/4 3* but self-inflicts 2 poison damage every turn after to min 6. Good late round card, risky early on... Good to counter opp poison and the min means if Russell hit you in elo
the min would stop the backlash
OP or not?