+3 Attack per 4 Life would be fairer, but I wanted to keep the ability short as written. I'm not sure Team: Reprisal: +3 Attack Per 4 Life Left would fit in the ability space.
My own suggestion would barely do so itself... As it is, I agree Thoazol, but feel the need to keep space in mind.
8/4 Ability: Reprisal: -1 Opp Pillz Per Damage, Min 6.
Perhaps a little OP, but it does have Reprisal and a Min of 6 to that Pillz manip.
7/3 Ability: Defeat: Poison 3, Min 9.
Very high min means this is strictly an elo
card. Also you have to lose with this and another card before the ability takes effect, and lose 3 rounds to reach the Min. However, if you take a risk, it might pay off...