Atraxa's Annihilation

For each {g} spent to cast this spell, you may play an additional land this turn.
For each {w} spent to cast this spell, create two 1/1 colorless Phyrexian Mite artifact creature tokens with toxic 1 and "This creature can't block."
For each {u} spent to cast this spell, scry 1, then draw a card.
For each {b} spent to cast this spell, each opponent exiles a card from their hand.