Kaj-Mortas, Praetor's Neophyte

Other creatures you control enter the battlefield with additional +1/+1 counters on
them for each color among permanents you control.
{2}{b}{g}, Sacrifice a creature: Put X -1/-1 counters on target creature, where X is the sacrificed creatures toughness. That creature gains infect. (Creatures with infect deal damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)