Revival

If a card in a graveyard has {X} in its mana cost, X is considered to be 0.

To double a player's life total, that player gains as much life as needed so that their life total is twice the number it was before. If their life total was negative, that player loses as much life as needed so that their life total is twice as far below 0 as it was before. Other effects interact with this life gain or loss accordingly.

If an effect allows you to cast a spell with certain characteristics, consider only the characteristics of the half you're casting. For example, if an effect allows you to cast a sorcery spell with mana value 2 or less from among cards in your graveyard, you could cast Assault this way, but not Battery.