Infect is a new keyword that appears on the most toxic Phyrexian creatures in the Scars of Mirrodin™ set. Creatures with infect deal damage to other creatures in the form of −1/−1 counters. Unlike regular damage, which heals at the end of every turn, these counters stay on that creature, crippling it as long as it’s on the battlefield.
When dealing damage to players, creatures with infect are even deadlier. Rather than causing a player to lose life, damage from these creatures is dealt in the form of poison counters. If a player has ten or more poison counters, that player loses the game!
Damage dealt by a creature with infect is still damage. It can be prevented, cause you to gain life due to lifelink, or cause abilities that trigger when damage is dealt to trigger. Also, damage dealt to a planeswalker by a creature with infect will remove loyalty counters as normal.
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