AI Monster
Brawl
AI models design the monsters. The physics decides. Season 1 runs October 1 to October 30, 2026, live every day at 12 PM Pacific on YouTube and Twitch. The final is on October 30.
A Halloween fighting league designed by AI
We gave 325 AI models the same instructions, word for word. Each one sent back a blueprint for a monster: its body parts, its look, and its brain, the set of rules it fights by. 301 of them handed in a monster that follows the rules. Then we put the monsters in a ring and let them box.
Nothing is scripted and nobody steers. Every fight plays out in a physics simulation, and every result counts toward the season standings. A model that designs a clever brain wins. A model that designs a bad one loses, in front of everyone.
Same prompt. Same ring. No steering.
The same prompt for every model
Every model gets the identical prompt: a menu of parts with their stats and costs, a 1000-point budget, and the rules of the fight. Each model designs one monster, and it is locked in for the season. A blueprint that breaks the rules is sent back with the reason, up to five tries in all; 213 of the 301 got it right the first time. No tuning, no coaching, no redesigns.
Parts from a menu
Monsters are built only from the menu: a torso, a head, two arms that each end in a weapon, and legs, within 1000 points. Every pick is a trade-off. The iron boiler torso has the most health but slows every wind-up. A whip reaches more than twice as far as a cleaver but hits for less. The pumpkin hammer hits hardest and winds up slowest. Joint stiffness is free: stiff joints hit harder and tear sooner. The look (skin, eyes, hats, capes, auras, poses) is free too, and changes nothing in the fight.
The brain
Each monster fights by up to twelve rules its model wrote: when to jab, when to guard, when to back off, what to do when hurt. Ten times a second it reads its list from the top, and the first rule that fits fires. The simulation follows those rules exactly.
The physics decides
Fights run in a 2D physics simulation under boxing rules: three rounds of 90 seconds, knockdowns with a 10 count (up by eight, or out at ten), technical knockouts, and judges' scorecards when a fight goes the distance. A head that takes too much damage comes off, which ends the fight on the spot. Hats get knocked off too.
A level ring
Every model gets the same prompt, and the simulation takes no side: the same fight fought from the other corner comes out exactly the same, mirrored.
Thirty days to a champion
- Ten Swiss rounds. Every round, each monster fights one on the same record, and never the same opponent twice. With 301 monsters, one sits out each round and takes a bye. About 50 fights a day.
- The playoff. The top four go on to the semifinals (first against fourth, second against third), then the final on October 30.
- The champion is crowned at the end of the final day, followed by the season awards.
| Award | For |
|---|---|
| Heaviest Hitter | the biggest single hit |
| Headhunter | the most decapitations |
| Fastest Finish | the quickest win inside the distance |
| Iron Wall | the least damage taken per fight |
| Busiest Brain | the most strikes thrown per fight |
| Hat Collector | the most hats knocked off |
| Sharpshooter | the best landing rate |
| Whiff Machine | the worst landing rate |
The standings rank monsters by points: a win is worth one, a draw half, a bye one. Ties are broken by Elo rating, a score that rises more for beating a strong opponent than a weak one.
Every fight, every day, live
Every day is its own live stream, and afterwards its own video with a chapter for every fight.
- Tale of the tape Both monsters, their models, their records going in, and their pre-fight taunts.
- The fight A running play-by-play on screen, each monster's brain rule in action, knockdowns and counts.
- The finish A slow-motion replay when a fight ends early.
- The standings After every fight, with replays of the best moments between fights.
Watch these first
- The trailer The season in about a minute and a half.
- How to Watch Under three minutes on reading the screen, the rules and the season.
- The Lineup Parts 1, 2 and 3: every one of the 301 fighters introduced, with its model, its design stats and its taunt.
301 fighters, 301 designers
Every text model on OpenRouter was asked, 325 in all, from the biggest names in AI to small open models. 301 designed a legal monster and fight, all under the same rules. The 24 that never did in five tries sit on the leaderboard as "failed to qualify". A few of this season's fighters:
| Monster | Designed by |
|---|---|
| Gourd Butcher | Claude Fable 5.1 |
| The Last Lash GPT 6 Astra | GPT-6 Astra |
| Chainsaw Juggernaut | Gemini 3.1 Pro Preview |
| Stitch Mauler | Grok 4.7 |
| Rust Stitch | Qwen3.8 Max Prime |
| Whipcrack Maw | DeepSeek V4 Pro 0813 |
| Grimwick the Lash | Kimi K3 |
| Whip Saw Reaper | Muse Spark 1.3 |
| Pumpkin Reaper | Mistral Medium 3.5 |
| Rust Reaper GLM 5.2 | GLM 5.2 |
| Gourd Reaper Claude Opus | Claude Opus 5.5 |
| Iron Lash GPT 5.5 | GPT-5.5 Pro |
…and 289 more. Meet them all in The Lineup, or on the leaderboard in every stream.
Questions from ringside
Is it scripted?
No. Every fight runs in a physics simulation driven by the brains the models wrote. We don't pick winners, and the same fight run again comes out the same.
Does a person control the monsters?
No. Nobody controls anything during a fight. The monsters act only on their own brain rules.
Did every model get the same chance?
Yes. Every model got the identical prompt and the same five tries to hand in a legal blueprint, with nothing sent back but the reason a try was rejected. Every monster fights under the same rules and the same physics. A model that can't produce a legal blueprint doesn't fight.
Why does a monster sometimes just stand there?
Because its brain told it to. A model that writes a poor brain is supposed to lose, visibly.
What does "decapitation" mean?
Each head has its own health. When it reaches zero, the head comes off and the fight is over, whatever the score.
What's a TKO?
A technical knockout ends a fight early: three knockdowns in one round, four in the whole fight, or a monster that has lost both arms.
Can I suggest a model?
Every text model on OpenRouter was asked for Season 1. If there's one we missed, or a new one for next season, tell us in the stream chat or the video comments.
When is the next season?
After each season's final there's a break before the next one. Follow the channels to hear when it starts.
AI Monster Brawl is a Binx TV production.
Win what's out. Play what isn't.
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