Let me say up front that I didn't come up with this idea and I don't know who did. I've seen it make the magic.gg lists a couple of times and I thought it looked cool. If by some chance the deck's author reads this, thank you! I've had a lot of fun playing it and I never would have thought of it myself.

I'm calling it "Poison Burn" because it kind of plays like a burn deck, where you don't develop much of a board presence and just try to deal damage to your opponent as quickly as possible, except instead of actual damage, it's poison counters.

Why play Poison Burn?

Bad news first: this deck has a poor match-up against Boros Convoke, which has had a pretty large metagame share recently, and only a slightly better one against Mono-Red Aggro.

The good news is that this is one of the few decks I've found that is actually favored against Domain -- the feeling of seeing a turn-one Jetmir's Garden and thinking "oh good, this should be easy" is quite something, let me tell you. It also does pretty well against control and combo in general. And since it's not a significant presence in the metagame, opponents will have few relevant sideboard tools and little experience to draw on.

One thing I like about the play pattern is that you rarely get into situations where the game is "over before it's over". You never establish board control, so even if your opponent has nothing going on, they'll still feel like they could get back into it with a big creature. Similarly, even when you're looking down the barrel of lethal damage with only 6 or 7 poison counters racked up, there are still topdecks that could turn things around for you.

While I can't really call this a budget deck, it does feature more commons and uncommons than most. Check your collection; you might be closer to having this built than you think.

I've been playing this deck in ranked best-of-three matches on Arena for months now, and I think it's competitive. At least Tier 2, maybe Tier 1.5. If I were entering a Standard tournament tomorrow, this is what I'd bring.

The list

Here's my current configuration. The maindeck is pretty stable and doesn't have a lot of flexibility IMO, but my sideboard has changed a lot to try to adapt to the metagame.

About
Name Poison Burn

Deck
5 Island
3 Plains
1 Otawara, Soaring City
1 Eiganjo, Seat of the Empire
4 Seachrome Coast
4 Adarkar Wastes
1 Deserted Beach
3 Mirrex
4 Crawling Chorus
4 Skrelv, Defector Mite
3 Arcane Proxy
4 Prologue to Phyresis
4 Experimental Augury
4 Serum Snare
4 Bring the Ending
4 Fateful Absence
3 Gadwick's First Duel
4 Distorted Curiosity

Sideboard
1 Pithing Needle
2 Elspeth's Smite
2 Doorkeeper Thrull
1 Lion Sash
2 Unlicensed Hearse
2 Knockout Blow
1 Reject Imperfection
4 Vanquish the Horde

The game plan

This deck mulligans more than most. You should be willing to go pretty deep in search of an opening hand that can cast Crawling Chorus; Skrelv, Defector Mite; or Prologue to Phyresis. Trust in your draw spells to dig you out of it -- I'm not saying it's easy, but I've been known to recover from mulls to 4. If you've already taken a couple of mulligans then you can think about keeping on the basis of Experimental Augury or Bring the Ending, but I never feel great about it. The good news is that any hand that can cast one of those three poisoners, and has at least two lands, is an easy keep pretty much regardless of whatever else is in it.

In the first few turns, do whatever it takes to assign the first poison counter. If that means "wasting" a Fateful Absence or Serum Snare on an opposing Novice Inspector, so be it. Assigning at least one counter turns on all your proliferate spells, and your job gets easier from there. But if it gets to turn 4 or 5 and your opponent is still poison-free, I don't like your chances.

Use a combination of counterspells, bounce, removal, and Skrelv to get in as much early attacking as possible. Sooner or later your opponent will overwhelm this plan, but ride the train for as long as you can. Your toxic 1/1s are here for a good time, not for a long time. A suicidal charge may be a fine play as long as you're reasonably confident that you'll get even one poison counter out of it.

Depending on the match-up, you may eventually be able to go wide with Mirrex, but most commonly you're aiming to finish with a cavalcade of two-mana instants.

Because the deck is almost entirely one- and two-mana spells, it's usually pretty easy to use all of your mana every turn. It depends on what the opponent is up to, but if it's turn 2 and I have a Chorus or Skrelv that I could cast, but I also have a Prologue or Augury, I'll often hold the creature until I've got my third land, just to maximize mana efficiency.

Card choices & interactions

Creatures

Skrelv, Defector Mite is rarely used for protection in this deck. Primarily it's here to force through damage, and often it's just a regular attacker with Toxic 1. Take the time to learn what its ability does and doesn't do. Importantly, it does grant Toxic 1, which means a Crawling Chorus or mite can hit for 2 poison counters, and your Arcane Proxies, which normally don't give poison, sometimes can.

If you have a choice between playing a Chorus or Skrelv on turn 1, lead with the Chorus. If it gets Cut Down or Play-with-Fired, you'll still have a mite ready to attack on turn 2. The exception might be if you have multiple Skrelvs and you're expecting the first one to die.

If you think you'll attack with a Crawling Chorus next turn, don't hesitate to chump-block with it this turn. It could be your best chance to get any blocking value out of it.

You may be surprised by how often tokens from Mirrex are relevant in this deck. Because so many of our spells can be cast at instant speed, I often find myself waiting until my opponent's end step to see whether I can make a mite or not. If they're not pressuring me, I usually do it. You can always proliferate later, but mites need time to recover from summoning sickness. And going (moderately) wide with mites is a not-infrequent finishing strategy.

Removal & other answers

Bring the Ending is so often a hard counter in this deck that I frequently forget it isn't really, and cast it at times when the opponent can pay for it. So, uh, don't make that mistake. But overall the card is really good for us.

While I think that Get Lost is a stronger card than Fateful Absence in the abstract, I learned from bitter experience that the calculus is different for this deck. Basically, you need to be able to trade your 1/1s in combat sometimes. It's important to be able to attack into a Deep-Cavern Bat or Faerie Mastermind and have your opponent actually stand to lose something if they block. Likewise, it's important to be able to attack into something big knowing that you can make it a trade by following up with Gadwick's First Duel (more on that in a minute). If you're helping your opponent put +1/+1 counters on their creatures, you're giving up those opportunities. In contrast to maps, the clues you hand out with Fateful Absence are harder to spend leftover mana on, and take longer to affect the board state, which aligns with our tempo strategy.

As I said, be alert to the potential of Gadwick's First Duel as a removal spell. All your creatures are tiny, but if you send one attacking into, let's say, Sheoldred, the Apocalypse, you can follow up with a Duel and kill that blocker with the Cursed role. (In my experience, opponents almost always block in this situation. I don't know whether they think I'm dumb or they foresee the trade and decide it's worth it, but very rarely will you get to bluff your way into a free poison counter.)

Make sure you understand the intricacies of how the curse works. Cursing Regal Bunnicorn is good; the curse overrides the Bunnicorn's innate ability, leaving it as a 1/1 permanently. Cursing a Botanical Brawler is bad; you're actually just helping to grow it.

Always put the Cursed role on something, if you can afford to, even if you're cursing one of your own creatures. There is a small but non-zero chance that you will later find yourself holding a Serum Snare with no good targets other than the role.

Serum Snare really shines in this deck. Bouncing your opponent's turn 2 or 3 creature, giving them an extra poison counter and clearing the way for your next attack, is a huge tempo swing. Sometimes I pass on countering a creature just because I want to Snare it first. If it's late in the game and there aren't any better targets, feel free to Snare something random -- The Celestus, Up the Beanstalk, a map token -- just to proliferate. (Don't Snare food/clue/blood tokens if they could be sacrificed in response.)

Stupid spell tricks

But one of the best things you can do with Serum Snare is combo it with Arcane Proxy. It may take a few turns to play out, but imagine a sequence like this: Proxy, recasting a Prologue > Snare the Proxy > Proxy, recasting Snare, targeting the Proxy > replay Proxy, recasting another Prologue.

Note that you have to cast Proxy in order to flash back a spell. If you try bouncing an opposing Ossification to free your Proxy, you will temporarily have a 4/3, but you won't get to do anything cool with it.

In the course of dozens of matches I have only once cast a Proxy for full price, and that was probably a misplay. Don't entertain any ideas of trading with Preacher of the Schism or flashing back Distorted Curiosity. That's not how the card works, at least not for us.

The final chapter of Gadwick's First Duel is phenomenal in this deck, though I only run three copies of the saga because having two at once is awkward. This is very situational, but here's a rough priority order for which spells you want to double with chapter 3: Distorted Curiosity > Experimental Augury > Prologue to Phyresis > Serum Snare > Fateful Absence. If you haven't left one of those (or an Arcane Proxy) on top after scrying, but you do have one in your hand, hold on to it instead of trusting your deck to deliver.

When you proliferate with a Duel in play, you have to actually think about whether you want to add a lore counter or not. (If you're playing on Arena, the Duel will be selected by default, and you might want to de-select it.) Will you have both the spells and the mana to make good use of chapter 3? Can you do that while also leaving two or four lands untapped to threaten interaction? Waiting until your next turn is sometimes the best play.

While I love Gadwick's First Duel and Arcane Proxy, you'll see me sideboarding them out more often than any other cards. That's because spell-repeaters are necessarily slower and more situational than the spells they're repeating.

One last spell-slinging tip: if you're close to winning, but also close to dying from Sheoldred triggers, remember that those triggers use the stack and can be responded to. If you're lucky, you may be able to chain Prologues to Phyresis and win even as the specter of death looms over you.

Lands

This deck needs to get underway quickly, so playing untapped lands in the first two turns is non-negotiable. I figure I can get away with one Deserted Beach because it's not like I'm going to keep one-landers (er, most of the time...). When it comes to dual lands that do enter untapped early on, we'll take as many as we can get.

Mirrex is a great land in general, and especially here. It's hard for control decks to answer, and it often comes to the rescue when we're in topdeck mode.

I don't run The Seedcore primarily because I think our need for blue mana that can be spent on instants is too pressing. But maybe trying out one copy wouldn't hurt.

In the sideboard

Vanquish the Horde is for any go-wide decks but most especially for Boros Convoke. Most people seem to sideboard Temporary Lockdown against Convoke, but I prefer Vanquish because it hits all of their creatures, leaves you your Chorus tokens, and will usually cost about the same, in the match-ups where it matters.

Standard has enough recursion decks at the moment that I think some amount of anti-graveyard tech is a necessity. Lion Sash and Unlicensed Hearse are the graveyard hate in my sideboard at the moment, and I wrote this guide with them in mind. But Rest in Peace recently got reprinted in The Big Score, and I think there's an argument that it would be worth the collateral damage to our Arcane Proxies (which we'd definitely have to board out) and Crawling Choruses. Then again, if your opponent brings in Pick Your Poison as counter-hate, your artifact creatures can run interference for Sash or Hearse better than Gadwick's First Duel can for Rest.

If all of these cards are too rare for your budget, Soul-Guide Lantern is a decent substitute, but I think you'll find that it's just not as robust as the others.

Match-ups & sideboarding

Atraxa Domain

No changes. You are already favored and you don't have any silver bullets that answer anything in particular. They run Cavern of Souls so I would not bother bringing in Reject Imperfection, and expect to use Bring the Ending against things like Sunfall rather than things like Atraxa. A resolved Atraxa or Herd Migration is probably game over within a couple of turns; you just have to win faster, but that's a realistic goal because their answers don't line up well with what we're doing. They usually can't interact sooner than turn 3, so it shouldn't be hard to start poisoning them.

If a Gadwick's First Duel gets trapped under a Temporary Lockdown, you can Serum Snare the Lockdown on their end step and use the proliferation to proc the Duel's first two chapters right away, then untap and finish it off. (And hopefully you can get in with a Chorus or Skrelv before they replay the Lockdown.)

Azorius, Dimir, or Orzhov Control

As with Domain, you're favored and don't have to change too much, but −1 Arcane Proxy +1 Pithing Needle can be worthwhile if you had trouble with planeswalkers or Restless lands. They'll be able to outclass or sweep away your creatures eventually, but it'll be harder for them to deal with your Prologues and Auguries, which they have to answer one-for-one while still trying to develop their own board. Cast your instants on their end step if you can (always good advice, but even more so here). Bluff counterspells, being mindful of the fact that they may be waiting for a window to resolve The Wandering Emperor. If the game goes long, Mirrex can be one of your most valuable assets (though they likely have Field of Ruin for it).

Some of my earlier builds had Skrelv's Hive in the sideboard. If you do that, this would be the time to bring it in.

Esper and other midrange

This is a fairly even match-up, winnable if you play carefully and/or luck breaks your way. Esper is probably the toughest midrange variant: Raffine is a monster, and their maindeck Dennick, Pious Apprentice shuts down your Arcane Proxies (sideboard out some or all of them). Golgari is probably the easiest variant. I don't have much experience against the Grixis Crimes deck yet, but I'd guess that it fits in this category, from our perspective. Bring in Reject Imperfection, somewhat counterintuitively, if you're worried about big, hard-to-kill threats like Aclazotz, Deepest Betrayal.

Rakdos or Boros Discover

Even to slightly favorable; from our perspective these are midrange decks with extra combo potential. −1 Arcane Proxy +1 Pithing Needle if you saw a planeswalker. Doorkeeper Thrull would stifle Geological Appraiser and Trumpeting Carnosaur; is that good enough? I might test it sometime.

Boros Convoke

−1 Fateful Absence
−2 Bring the Ending
−2 Gadwick's First Duel
−3 Arcane Proxy

+2 Elspeth's Smite
+2 Doorkeeper Thrull
+4 Vanquish the Horde

I used to bring in Knockout Blow, but I stopped because the majority of their creatures are not red. I'm sideboarding out 2 Bring the Ending because they have Cavern of Souls, but keeping 2 because they also have Case of the Gateway Express and Warleader's Call.

Flash Doorkeeper Thrull in response to any creature that would generate an ETB trigger, be it Knight-Errant of Eos or merely Voldaren Epicure, but expect to lose the Thrull to your own Vanquish later on.

Mono-Red or Gruul Aggro

My advice for fighting red aggro with this or any other deck is to forget about your own game plan and just try to stop theirs. If you can stabilize, you can take your time about winning. Chump-block pretty much any time it would save more than one life point. Remember that the back side of Kumano Faces Kakkazan prevents you from getting tokens out of your Choruses, but you may not have the luxury of playing around that.

−2 Fateful Absence
−1 Gadwick's First Duel
−1 Arcane Proxy

+2 Elspeth's Smite
+2 Knockout Blow

Vanquish the Horde is a maybe. The sorcery speed is a drawback; what you really want is to be able to respond to a Monstrous Rage. It might be better against Gruul, which leans more heavily on creatures. Different builds of mono-red can be more creature-focused or more spell-focused, and it can be hard to guess which you're dealing with just from seeing one game. Even if you do board in Vanquishes, I would probably not take all four copies. Cut Duels and/or Proxies to make room.

Temur Lands Combo

This match-up is tricky but winnable. It gets a lot better if you can find one of your sideboard cards. Failing that, slow them down by bouncing/killing/countering their Nissas and Aftermath Analysts (but remember that Analyst's ability can be activated at instant speed and without tapping). See if you can hold a Bring the Ending for Worldsoul's Rage.

−1 Fateful Absence
−2 Gadwick's First Duel
−1 Arcane Proxy

+1 Pithing Needle
+2 Unlicensed Hearse
+1 Lion Sash

If you find your Pithing Needle, name Aftermath Analyst. It doesn't stop their combo but it slows it down a lot. Equip Lion Sash to another creature if you can spare the mana, to save it from (the first) Ill-Timed Explosion. Wait until their end step to activate Sash or Unlicensed Hearse, so you'll always be ready to respond if they try to recur something, and consider reserving a Serum Snare to save the Sash/Hearse from an Abrade. Exile their cards in this order of preference: anything they're trying to bring back right now > Memory Deluge (unless they're still a few turns away from casting it) > fetch lands > other lands > Shigeki, Jukai Visionary > Worldsoul's Rage > Nissa, Resurgent Animist > Aftermath Analyst > Virtue of Strength > other creatures > other spells. Don't assume that Bring the Ending is a get-out-of-jail-free card; they probably board in Negate.

Azorius Djinn & Mentor

If you're not familiar, this deck has a low creature count, sometimes just Haughty Djinn and Monastery Mentor but sometimes with a supporting actor like Picklock Prankster or Fallaji Archaeologist, then tries to recur those creatures with Helping Hand or Recommission. A high density of cheap cantrips lets them go wide (with Mentor) or tall (with Djinn) to finish the game quickly.

−3 Gadwick's First Duel
−3 Arcane Proxy

+1 Lion Sash
+2 Unlicensed Hearse
+3 Vanquish the Horde

This is a lot like Temur Lands in that it's a tricky match-up that improves significantly if you can keep their graveyard empty. Again, remain vigilant for your chance to exile something in response to a spell. Here's your priority order: anything that's being targeted right now > Monastery Mentor > Otherworldly Gaze > other instants & sorceries > Haughty Djinn > anything else. Move Haughty Djinn up a couple of notches if there are so many spells in the graveyard that you won't be able to exile them fast enough to keep a Djinn's power low. Chump-block freely, keeping in mind that they can grow their prowess creatures at instant speed.

The mono-blue predecessor that usually runs some number of Tolarian Terror is an easier battle. Sideboard in the same graveyard hate but not the sweepers. They have more counterspells and will never cast a Djinn if they can't protect it, so be prepared to fight a counter war over it.

Simic Artifact Aggro

This deck can put you on a pretty fast clock without warning. It helps if you can hold up interaction to respond to a Zoetic Glyph on the stack. Their animated tokens are pretty Snareable, just pay attention to whether they can sacrifice them in response. You may have to do a lot of chump-blocking. I don't know if there's anything to sideboard for this -- Elspeth's Smite is generically good against aggro, but the Simic deck can make X/4s a little too easily. I'd rate the match-up as maybe slightly unfavorable, but far from hopeless.

Selesnya Enchantments

I haven't seen Enchantments around in a while, and I don't miss it. Like Simic Artifacts, it can rack up a lot of power pretty quickly. And also like Artifacts, most of their cards are low-cost and make good Serum Snare targets. That's the advantage that you want to exploit if you can. Bringing in some number of Vanquish the Horde may be worth it, especially if their build looks token-heavy with things like Teachings of the Kirin.

Orzhov Lifegain

We don't care about their life total, but we do care about how big Amalia Benavides Aguirre and Voice of the Blessed can get. Fortunately they have a lot of good targets for Serum Snare.

They have a lot of ETB triggers, from Lunarch Veteran and Elas il-Kor and so on. Could bringing in the Doorkeeper Thrulls (in exchange for one each of Proxy and Duel, I think) be good? I don't have a lot of experience against this deck, but I'll give it a try next time.

Bant Poison

I think this match-up is unfavorable; they're trying to do the same thing we are, but they're faster at it.

−4 Fateful Absence

+4 Vanquish the Horde

Vanquish over Absence will help you work around their Skrelvs and Venerated Rotpriests. But you definitely have to get a little lucky to win this one.

Jodah Legends

I think you're at least slightly favored, because they take a while to set up, but an early Skrelv can stymie your removal, and an early Thalia can stymie your entire game plan. I don't think there's anything in the sideboard to bring in here, but maybe value Fateful Absence a little higher when mulliganning.

Dinosaurs & other Fight Rigging decks

Slightly favorable. Kill or bounce their early mana-producers if you can. Bring the Ending is valuable here because Palani's Hatcher or Hulking Raptor become big problems if they resolve. If you missed your chance to counter a Fight Rigging, see if you can let them pour more effort into it before you deal with it -- e.g., let them target something to put a counter on and then bounce or kill the target. Most of their creatures are green, so Skrelv should often let you attack through them. −1 Arcane Proxy +1 Reject Imperfection is at least worth consideration.

Rotation

The core of this deck is from Phyrexia: All Will Be One, which should remain in Standard until August of 2025, but we will lose a few cards this year. The biggest loss will be Fateful Absence (from Innistrad: Midnight Hunt). As discussed above, I don't think Get Lost is an acceptable substitute in this deck in particular. After looking through the two-mana white removal in Standard, I think our best replacement is probably Soul Partition. When you think about it, Partition is sort of like Absence, if the card your opponent draws off the clue were guaranteed to be the same one you killed. Oh, and it can't answer the Restless lands. Those drawbacks aren't great, but Partition does offer the ability to target enchantments and artifacts, as well as the potential to save and re-use your own creatures. It's worth a try at least. And who knows what other analogues may arrive in future sets?

Playing against the deck

I've only once seen an opponent playing something that might have been Poison Burn. I definitely don't think you can justify dedicating sideboard slots to it. But if you do find yourself facing it, here's some advice.

It may be hard to distinguish this deck from Bant Poison in the early turns. Green-producing lands would be an obvious clue. Additionally, Jawbone Duelist, Skrelv's Hive, and Annex Sentry are seemingly fitting white cards that I personally would not maindeck in the Azorius version.

Fight like hell to avoid getting the first poison counter. Don't Cut Down a Chorus on your own turn; do it on their turn so the Mite has to wait to attack -- but you may want to do it during their upkeep, before they've played a land or possibly drawn a counterspell. If you play Deep-Cavern Bat on turn 2, you may find that the Poison player has only one card that can actually poison you. That's probably a good choice.

When it comes to building your defenses, more creatures is better than big creatures. If the Poison player makes an odd attack, suspect Gadwick's First Duel (or Eiganjo). That doesn't necessarily mean you shouldn't block, but factor it into your decision.

When sideboarding: sweepers are fine but they can't be your whole plan, because (a) Crawling Chorus replaces itself, (b) Mirrex makes mites at instant speed, and (c) after the first few turns, the spells do most of the work. Negate or Spell Pierce shouldn't lack targets. One-for-one removal is bad unless it's cheap, like Cut Down. In particular, Go for the Throat has only Crawling Chorus as a potential target, so you should definitely take that one out.

Weakening your own plan to bring in graveyard hate is inadvisable. My build has only three Arcane Proxies for recursion, and they're often the first things to get boarded out. But if you have access to incidental graveyard hate like Lord Skitter or Graveyard Trespasser, that's probably worthwhile.