Star Staff

Whenever you would produce mana, you may choose to store it in Star Staff instead. Stored mana cannot be removed or used for other purposes. Mana stored in Star Staff does not empty between turns. You may cast Shario from Star Staff when it has at least 10 stored mana: Shario — Sorcery {10}: Exile all nonland permanents your opponents control. Each opponent loses 10 life. This damage can’t be prevented.