Extinction Event

Ritual (Reveal and exile this card from your hand,
your graveyard, or your library at any time. As long
as it is exiled this way, you may pay any amount of
mana on each turn, noting the amount and type spent.
When you have spent enough this way to pay for this
card's casting cost, it gains flash and you may cast it
from exile for {0}. Shuffle it into your library after.)
All creatures lose hexproof and indestructible.
Extinction Event deals 15 damage to all planeswalkers and lethal damag