Dead of Nuclear Winter

When Dead of Nuclear Winter enters the battlefield with 10 Fallout counters on it.
At the start of each upkeep, remove a Fallout
counter and place a -1/-1 counter on each
creature without a gas mask.
Creatures with Gas Masks cannot be affected
by fallout when it is not your turn.
When there are no Fallout counters, exile
Dead of Nuclear Winter.
{5}: Create a Gas Mask Artifact Token. Any player may activate this ability.