Infect

Infect is a mono-green deck that ignores the opponent's life total entirely: it puts one cheap infect creature on the battlefield, Glistener Elf, Blight Mamba, or Ichorclaw Myr, and stacks pump spells onto a single attack so the poison counters pile up in one swing, often before the opponent has cast a second spell. It is a fringe choice in the current Pauper field, at 0.1% of the metagame, which cuts both ways: opponents rarely have a plan for it, and the field's most common removal and blockers were not tuned with a lone infect creature in mind, but the deck also gets no help from the shape of the metagame.

The deck beats ramp decks that spend their early turns building mana rather than answering the first attacker, midrange decks that trade one for one but are slow to put a blocker in front of it, and combo-control decks that need several quiet turns to set up. It is favored against Gruul Ponza, Grixis Affinity, Familiars, Naya Gates, and Gruul Ramp.

It struggles against fast aggro decks that race while spending cheap removal on the lone attacker, against tempo decks that hold a counterspell for the pump spell itself, and against control and combo decks that either sweep the board or simply win first. It is slightly unfavored against Mono Red Rally, and unfavored against Blue Terror, Mono Red Madness, Mono Blue Faeries, Jund Wildfire, Golgari Gardens, White Aggro, Black Sacrifice, and Ruby Storm.

Every card in this deck exists to do one thing: get a single infect creature to connect with the opponent while it is carrying enough pump to finish them. Glistener Elf, Blight Mamba, and Ichorclaw Myr are the only creatures that deal poison, and the rest of the deck is pump spells, protection for the attacker, lands that help it through, and Llanowar Augur, a creature you sacrifice in your upkeep to give the attacker +3/+3 and trample. The priority that decides games is keeping that one attacker alive and unblocked for the one combat that counts: you are not building a board, you are protecting a body long enough to cast Might of Old Krosa, Mutagenic Growth, and Embiggen on it in the same turn. Lifegain on the other side of the table is irrelevant, and so is the opponent's life total.

The engine is infect itself. Damage from the Elf, the Mamba, or the Myr is dealt to players as poison counters, and ten of them end the game, so a creature that would normally hit for eleven damage against a twenty-life opponent instead wins on the spot. Because every point of power on the attacker becomes a counter, a fistful of one-mana pumps on one creature does the work of an entire aggressive board. Escape Tunnel makes a small attacker unblockable for the turn, Rancor and a sacrificed Llanowar Augur give it trample so a chump block does not stop the counters, and Rancor comes back to hand whenever its creature leaves the battlefield, so the trample moves onto the next body.

A game runs in three short phases. Setup is a Forest and an infect creature, ideally Glistener Elf on the first turn. The payoff is the next attack: Might of Old Krosa cast before combat for its full bonus when nothing can block, then Mutagenic Growth paid with life and Embiggen after blockers are declared, which is enough poison to win from one swing off two lands, with no mana left over for a second body. If that attack falls short, the close is cracking the following turn so the same creature connects again and the remaining pumps finish the last few counters. Whichever of the Elf, the Mamba, or the Myr is carrying the pumps, the win is always poison.

Glistener Elf

The best card in the deck and the reason to keep almost any hand that has it with a Forest. A one-mana infect creature attacks on the second turn, which puts every pump spell in the deck a full turn ahead of where Blight Mamba or Ichorclaw Myr would put them, and the fastest kills this deck produces all start with the Elf on turn one. It dies to everything, so cast it first and spend the protection spells on it rather than on a later body: the Elf carrying two pumps is worth more than any other creature you will draw.

Blight Mamba

The two-mana infect creature that is hardest to keep off the battlefield, because two more mana regenerates it. Against damage-based removal and in combat it is the attacker you can commit to, and in a longer game it is the deck's mana sink: attacking into a bigger creature with regeneration mana open leaves the blocker with a permanent -1/-1 counter and costs you nothing but the regeneration mana. It is the body to lead with when you expect the opponent to spend a kill spell on the first creature you show.

Ichorclaw Myr

A colorless two-mana infect creature that punishes blocks: whenever it becomes blocked it gets +2/+2 until end of turn, so a blocker that steps in front of it takes three -1/-1 counters rather than one, and with trample from Rancor or Llanowar Augur the extra power spills over as poison. Attack with it into boards that want to block; the opponent usually has to choose between losing the blocker and taking the counters.

Rancor

Infect is a linear, tempo-positive aggro deck with a three-turn clock and close to no inevitability: it has no card draw, no removal, no counterspells, and no discard in the main deck, and its only interaction is protection for its own attacker in Snakeskin Veil and Vines of Vastwood. That makes it the beatdown in essentially every matchup class. What changes from class to class is which of the deck's pressure points the opponent is attacking: how fast they can kill or neutralize the first attacker versus how fast the pumps turn it into ten poison, whether their removal is targeted (where protection works) or edicts, sweepers, and counters (where it does not), whether they can keep blockers in the way faster than Escape Tunnel, Rancor, and Llanowar Augur clear the path, and how much life you can afford to spend on Mutagenic Growth against their own clock.

Vs. Aggro. You are still the beatdown, because poison finishes faster than their damage does, but this is the one class where your own life total is a resource under attack. The defining play is deciding whether to pay two life for Mutagenic Growth when it makes the attack lethal now versus holding it as a cheap way to survive a turn; if the pump ends the game, pay the life, and if it only adds a few counters, keep the life and let Llanowar Augur block. Their removal is usually cheap burn pointed at your one creature, so this is also the class where Blight Mamba with regeneration mana open earns the most.

Vs. Midrange. Beatdown, and the matchup is a fight over the shape of their removal. A midrange deck answers threats one at a time with targeted kill spells, so the play that defines the role is attacking with a creature and passing priority with Snakeskin Veil or Vines of Vastwood mana open, then only adding pumps once they have committed or declined to commit a removal spell. Blockers matter more here than against aggro, so the order in which you deploy Escape Tunnel and is what turns a stalled board into a lethal one.

1. Activate Escape Tunnel and let it resolve before any pump goes on the stack, including the upkeep Llanowar Augur sacrifice, and keep Rancor off the creature you plan to tunnel. The Tunnel can only target a creature with power 2 or less, and if the power climbs past that while the ability is still on the stack, the ability does nothing; once it has resolved, every later pump still connects unblocked.

2. Hold instant-speed pumps until blockers are declared and the opponent has passed priority, and keep Snakeskin Veil or Vines of Vastwood mana open until they commit a removal spell. Pumping into open mana lets one kill spell answer the creature and every pump already on the stack with it. Waiting means each removal spell they fire costs them a card, and a protection spell cast in response makes their removal fizzle while your pumps still resolve afterward. Edicts and sweepers ignore hexproof entirely, so against those the protection is a second body on the battlefield, not a Veil held in hand.

3. Cast Might of Old Krosa in the precombat main phase for its full bonus only when the attacker is already unblockable or the opponent has no untapped creatures; otherwise hold it as an instant-speed +2/+2 after blocks. The bigger mode needs a main-phase cast, and the postcombat main phase comes after damage, so the real choice is a telegraphed +4/+4 before blockers or a surprise +2/+2 after them. A large attacker shown early invites a chump block or a double block that a 1/1 would have walked past. When the opponent has nothing untapped, the main-phase cast is the fastest kill the deck has: Forest and Glistener Elf on turn one, then on turn two a second Forest, Might of Old Krosa before combat to make the Elf a 5/5, attack, and after blockers Embiggen for a 9/9 and Mutagenic Growth paid with two life for an 11/11. That is eleven poison off two lands.

4. Count Embiggen as +4/+4 on Glistener Elf and but only +3/+3 on when you add up poison. The spell grows the creature by one for each card type and subtype it has: the Elf (Creature, Phyrexian, Elf, Warrior) and the Myr (Artifact, Creature, Phyrexian, Myr) carry four each, while the Mamba (Creature, Phyrexian, Snake) carries three, and the bonus is fixed as the spell resolves. A lethal count that treats Embiggen as a flat number comes up one poison short on the Mamba, which is exactly the kind of miscount that leaves the opponent at nine.