Creeping Chill

The card you never cast. The top half (a four-mana sorcery for three damage and three life) is bait, a rate nobody pays. The whole reason this exists is the second clause, which fires when the card is put into your graveyard from your library, turning every self-mill effect into a Lava Spike that also gains you three life. A burn-and-drain spell that punishes you for drawing it and rewards you for binning it inverts how spells normally work: the deck wants it dead in the library, not live in the hand, and stacking three or four copies behind a mill engine like Stitcher's Supplier or Hedron Crab converts a defensive graveyard strategy into a clock. That alignment, mill as offense rather than as a route to a graveyard payoff, is the design idea here, and it is what let graveyard-aggro variants close games instead of purely grinding value. The exile clause is worded as a choice ("you may"), but in practice you almost always take it: the damage and lifegain are free, and even against graveyard hate, declining only leaves the card sitting where hate can strip it for nothing. The card is built to be milled, never seen, and counted on for nine or twelve damage spread across a game you never had to spend a card or a mana to assemble.