Devourer Combo

A two-card kill wrapped in fast colorless mana. Tinker is {2}{U} with an additional cost of sacrificing an artifact, and it searches your library for an artifact and puts it straight onto the battlefield — so a turn-two Mind Stone becomes a turn-three Phyrexian Devourer without paying its {6}.

Phyrexian Devourer is a 1/1 artifact creature with two lines that matter. “Exile the top card of your library: Put X +1/+1 counters on this creature, where X is the exiled card’s mana value,” and “When this creature’s power is 7 or greater, sacrifice it.”

The second line is a trigger, not a replacement effect, and that’s the whole combo. Activate the exile ability until the power crosses 7. The sacrifice trigger goes on the stack — and while it’s sitting there, you still hold priority and can keep exiling. Pump it to 30, 40, whatever your library supports, then respond to the trigger by sacrificing the Devourer yourself.

There are two ways to cash it in. Altar of Dementia is a {2} artifact reading “Sacrifice a creature: Target player mills cards equal to the sacrificed creature’s power,” which decks them on the spot. Fling costs {1}{R}, takes a creature sacrifice as an additional cost, and deals damage equal to that creature’s power to any target. Either way the trigger finds no creature and does nothing. Two cards, no attack step, no combat.

Defense Grid is the protection. Every spell costs {3} more except during its controller’s turn, so on your combo turn a Landstill deck holding Counterspell and Swords to Plowshares simply can’t afford to interact. It’s a {2} artifact, which also makes it food for Tinker.

The mana is built for speed: Ancient Tomb and City of Traitors each tap for {C}{C}, Mind Stone and Chromatic Sphere ramp and replace themselves, and Gemstone Mine and Shivan Reef supply the blue and red. Chromatic Sphere is doing triple duty — fixing, a cantrip, and a spare artifact to sacrifice to Tinker.

The deck is fragile in the way all two-card combos are. Instant-speed artifact removal on the Altar of Dementia breaks it, Powder Keg and Nevinyrral’s Disk sweep the whole board, and a counterspell landing before Defense Grid usually costs you the game. Note also that you’re exiling your own library to combo, so a fizzled attempt can leave you with nothing left to draw.