Doorway of Worlds

Lands you control have "{t}: Add one mana of
any color."
{w}{u}{b}{r}{g}: Exile the top two cards of your
library. You may play them this without paying
their mana costs for as long as they remain in
exile.
{w}{w}{u}{u}{b}{b}{r}{r}{g}{g}: Destroy all permanents
you don't control, then exile Doorway of Worlds.