The Kami Spirit Gate

Whenever a Spirit creature enters the battlefield
under your control, you may untap The Kami
Spirit Gate.
{t} Add {1} to your mana pool.
{x}{t} Discard X cards.You may cast X Spirit
creature cards from your graveyard and your
hand this turn without paying their mana costs.
Exile Kami Spirit Gate.
It began in the swamps of Kamigawa.