Gateway Between Worlds

{t}: Add {c}{c}{g}{g} to your mana pool.
{10}{g}{g}{g}{g}{g}, {t}, Sacrifice Gateway Between
Worlds: Exile all cards in play, in players hands,
and in all players graveyards. Then, each player
reveals the top 15 cards of their library. Put all
permanents onto the battlefield, and exile all
non-permanents with a Gateway Counter. Create
a token that says, "Each player may cast cards
with Gateway Counter on them at anytime
without paying its mana cost." Exile Gateway
Between Worlds.