Throes of Chaos

A blank sorcery is an unusual thing to build an engine around, and the trick here is that the card's only effect is its own resolution: cast it, cascade fires, and you cast whatever it finds under four mana value for free (or nothing, if it exiles no eligible nonland card or you decline the hit). What keeps the roll from being a one-time gamble is retrace. This is not an activated ability; it is a second way to cast the same card, this time from the graveyard by discarding a land alongside the mana. So every flooded draw becomes another cascade trigger. The two mechanics cover each other's blind spots precisely. Cascade off a single card is a lone throw of the dice; retrace on an ordinary spell just replays a known effect. Fused, retrace makes cascade repeatable and cascade gives retrace a payoff worth recurring for. Four mana value also anchors the outcome: the cascade window is wide enough that a curve-conscious deck lands on something live rather than whiffing into top-heavy dead weight. The honest price is that you never choose the hit, so the yield tracks exactly how dense your library is beneath the threshold. Build so the misses are rare and each discarded land laundered from hand buys a spell you never had to draw. That is the entire design: a mana-and-land sink that drips gas one random result at a time, without demanding any further combo assembly around it.