Accepted Antidote

(If all players agree, you may start the game with
this decree face up in the command zone.)
When Accepted Antidote is in the command
zone, players can't lose the game when they have
a specific number of poison counters. Instead,
at the beginning of each player's end step, that
player loses 1 life for each poison counter they
have, then removes one poison counter.
Pick your poison...