Pestilence

When Pestilence enters the battlefield, each
creature gets -X/-X until end of turn.
When creatures you control deals combat damage
to a player, they get that many poison counters.
"It was such a frightful thing that when it got into a
house, as was said, no one remained. Frightened people
abandoned the house and fled to another."
-Marchione di Coppo Stefani