Throes of Chaos (150) (MH1)

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom of your library in a random order.)
Retrace (You may cast this card from your graveyard by discarding a land card in addition to paying its other costs.)