Nurgle, Prince of Rot

Infect
Creatures have wither.
Creatures you control get +1/+0 for each -1/-1
counter on them.
When you cast this spell, each player gets a
poison counter.
Nurgle, Prince of Rot costs {1} less for each
poison counter on players.
Nurgle, Prince of Rot gets +1/+0 for each
poison counter on players