Shagaru Magala, The Frenzy

Flying, first strike, wither
Whenever an opponent would gain life, you may
have that player gain a virus counter instead.
Whenever Shagaru magala, The Frenzy deals
combat damage to a player, proliferate, then give
that player a virus counter.
At the beginning of your end step, each of your opponents lose life equal to the number of virus counters they have.