Magic: The Gathering Comprehensive Rules Changes - Planar Chaos to Future Sight

Old rule (Planar Chaos)	New rule (Future Sight)
Prevention Effect [Click to view all changes.]
Prevention Effect Effects that prevent something from happening replace it with "do nothing." (See rule 419, "Replacement and Prevention Effects.") A prevention effect must be active before the event it's intended to prevent. Effects that prevent a specific amount of damage act as "shields" and stay active until that amount of damage has been prevented or the turn ends. The damage doesn't have to be dealt by a single source or all at once. Effects that prevent the next damage from a specific source apply the next time that source would deal damage, regardless of the amount. These effects expire when the turn ends. See rule 419.8, "Sources of Damage."	Prevention Effect Effects that prevent something from happening replace it with "do nothing." (See rule 419, "Replacement and Prevention Effects.") A prevention effect must be active before the event it's intended to prevent. Effects generated by the resolution of a spell or ability that prevent a specific amount of damage act as "shields" and stay active until that amount of damage has been prevented or the turn ends. The damage doesn't have to be dealt by a single source or all at once. Effects generated by static abilities that prevent a specific amount of damage prevent only the indicated amount of damage from any applicable source at any given time. Effects that prevent the next damage from a specific source apply the next time that source would deal damage, regardless of the amount. These effects expire when the turn ends. See rule 419.8, "Sources of Damage."

Old rule (Planar Chaos)

New rule (Future Sight)

Prevention Effect [Click to view all changes.]

Prevention Effect

Effects that prevent something from happening replace it with "do nothing." (See rule 419, "Replacement and Prevention Effects.") A prevention effect must be active before the event it's intended to prevent. Effects that prevent a specific amount of damage act as "shields" and stay active until that amount of damage has been prevented or the turn ends. The damage doesn't have to be dealt by a single source or all at once. Effects that prevent the next damage from a specific source apply the next time that source would deal damage, regardless of the amount. These effects expire when the turn ends. See rule 419.8, "Sources of Damage."

Prevention Effect

Effects that prevent something from happening replace it with "do nothing." (See rule 419, "Replacement and Prevention Effects.") A prevention effect must be active before the event it's intended to prevent. Effects generated by the resolution of a spell or ability that prevent a specific amount of damage act as "shields" and stay active until that amount of damage has been prevented or the turn ends. The damage doesn't have to be dealt by a single source or all at once. Effects generated by static abilities that prevent a specific amount of damage prevent only the indicated amount of damage from any applicable source at any given time. Effects that prevent the next damage from a specific source apply the next time that source would deal damage, regardless of the amount. These effects expire when the turn ends. See rule 419.8, "Sources of Damage."