Plagueus, the Horseman

+1: Put 2 -1/-1 counters on target creature. Until your next turn, whenever that creature attacks, put a poison counter on that creatures controller.
-2: Up to 3 target players get 2 poison counter, then each player with a poison counter loses 2 life.
-8: Double the number of -1/-1 counter on all creatures. Double the number of poison counters on all players.