cr:6.4.10j

A shielding-prevention effect is a prevention effect that acts as a shield. It prevents a specific amount of damage from any number of events that activate it. Shielding-prevention effects are typically written in the format “[CONDITION?] prevent the next [PREVENTION].” After a shielding-prevention effect prevents damage, any remaining prevention amount is used to prevent a future damage event. If the prevention amount of a shielding-prevention effect is reduced to zero, the effect ceases to exist.

Example: Bone Head Barrier has the text “Roll a 6 sided die. Prevent the next X damage that would be dealt to you this turn, where X is the number rolled,” which is a shielding-prevention effect that applies to every event that would deal damage to a player’s hero this turn until X damage has been prevented in total.