UFB's Ghost Trial: the engineer route into the league, and what Ultimate Bots says it offers

Ultimate Bots (UFB) has a second way in to its league besides piloting a robot in the arena. It calls the people on that route "ghosts", and its page for the monthly "Ghost Trial" challenge says the strongest ghosts get drafted for Season 2. This explains what the page says, and what it does not.

PILOTS AND GHOSTS

UFB's home page describes two roles. "Pilots drive full-scale humanoids in the arena. Ghosts build the Physical AI stack behind them." It adds that every team gets a league-assigned Unitree G1, so no robot purchase is required. Ghosts are described as engineers and builders working on physical AI, and signing up is a free account: UFB says creating an account is the registration. A "Current Ghost Trial" link on the home page leads to the challenge page.

THE CHALLENGE UFB DESCRIBES

The page read for this story is headed "Ghost Trial, Trial 04, The SuperSONIC Challenge" and calls the series a monthly physical AI challenge. Trial 04 ran from 21 August to 27 September 2026 and offered $3,000 in cash: $1,000 for each of three tracks, Martial Arts, Performance Arts and Experimental. The task was to teach a humanoid a move the stock model cannot yet perform. "Every month brings a new trial; the strongest ghosts get drafted for Season 2," the page says.

The method has five steps. Entrants pick a move, build a motion dataset, convert it to the format of SONIC (a whole-body control model whose checkpoint UFB released), fine-tune from that checkpoint using a provided recipe, and show the improvement in simulation against the stock baseline. UFB says entrants adapt a model rather than train one from scratch, and that everything runs in simulation, so no robot is needed. The page lists a $50 Nebius compute credit, starter scripts, a benchmark called WBT-Bench for self-scoring, and a text-to-motion tool inside Ultimate Bots Studio.

Judges decide each track. The listed criteria are the WBT-Bench score, the difficulty and originality of the move, how completely it lands, and how clean the dataset, configuration and pipeline are.

RULES

The trial is open worldwide, free, for individuals or teams of up to four. Entrants keep ownership of what they create. Winners grant UFB the right to run the winning skill on real robots and across its channels, which UFB describes as how the work gets on stage. The page lists the Unitree G1, Booster K1, Agibot X2 and LeRobot SO-101 as league robots. Submissions closed on 27 September, and the page says winners were to be announced live on 1 October.

WHAT UFB HAS NOT SAID

Roboxing has not found the Trial 04 winners, whether a newer trial is open now, how many ghosts have been drafted, what drafting involves, or any fight in which a ghost's work has run on a real robot. The page we read is the Trial 04 page, so a later trial may exist elsewhere on UFB's site or in its account portal, which we did not open. Season 2 begins at TwitchCon San Diego on 13 November, and UFB has not published a card for it.

For readers asking how to get into humanoid robot fighting: this is the route for engineers. Athletes and performers who want to pilot are covered in Roboxing's guide to becoming a robot fighting pilot.

SOURCES

Ultimate Bots, ultimatebots.com/hackathon (Ghost Trial, Trial 04) and ultimatebots.com (home page), both read 13 November 2026.