The symbol {X} represents an unspecified amount of mana. When playing a spell or activated ability with {X} in its cost, its controller decides the value of that variable.

• 则代表未定数量的法术力；若所使用的咒语之费用，或是起动式异能之费用中包含了{X}则由其操控者来决定该变量的数值。