Da Wid of the Toxic Vapors

Menace
Creatures you control have Venomous. (This
creature deals damage to creatures in the form
of -1/-1 counters and to players in the form of
Toxicity counters. If a player has a Toxic
counter, at the beginning of their upkeep, that
player loses 1 life per Toxic counter. These
counters empty after 1 use.)
"Swampy."