Warner Bros. San Diego Was Reportedly Working on Mario Kart-Like Racer Before Being Shut

Warner Bros. was reportedly working on a Mario Kart-like racing title that would bring together characters from the company's wide portfolio of IPs, including Adventure Time, Scooby Doo, Tom Jerry and more. The kart racer was in the works at Warner Bros. Games San Diego, which was shut down alongside two other in-house studios in February. Warner Bros. never announced the game, which is said to have gone through several iterations, from a free-to-play multiplatform title to a paid-for PC only release.

WB San Diego Was Working on a Mario Kart-Like Racer

The information comes from Colin Moriarty, who claimed on his Sacred Symbols podcast Monday that a former WB San Diego staffer reached out to him to talk about the unannounced project. The kart racer in development at the studio was codenamed “Moonlight” and could have potentially been titled “WB Racers” and “XDR,” or cross-drift racers, the source told Moriarty.

Just like Mario Kart's roster of Nintendo characters, the game would have featured Warner Bros IP, including Adventure Time, Tom and Jerry and more. Moriarty claimed he saw gameplay footage from the racer and said it was “heavily inspired” by Mario Kart. He described a game as a “drift racer running on Unreal Engine 5, with stylised graphics and fine vehicle control.”

The WB San Diego staffer told Moriarty that the project lacked “intention” and “coherent approach” and went through several changes through the course of its development. Project Moonlight reportedly kicked off as an online-only free-to-play title for PlayStation, Xbox, Nintendo Switch and mobile platforms. Towards the end of the development cycle, however, Switch and mobile ports were abandoned in favour of a PC version. Later, the kart racer reportedly became a paid-for PC only release, with console versions put on hold.

The game was reportedly greenlit during the pandemic and would've released via Steam Early Access. According to the source, WB San Diego staffed over 100 developers during the game's development cycle, which “started to come apart this past fall.”

Despite all the work on the game, it was never launched. The source said there was “quite a bit of animosity internally,” with WB San Diego staffers feeling it was unfair that Player First Games, another Warner Bros. Games studio, got to launch MultiVersus twice, but the kart racer did not see the light of day.

Last month, both WB San Diego and Player First Games, along with Monolith Productions, were shuttered after Warner Bros.' gaming division bled $300 million (roughly Rs. 2,627 crore) in losses in 2024. The company also cancelled the in-development Wonder Woman game and said it intended to refocus on its “bigger franchises” like Harry Potter, Game of Thrones and Batman, after a string of underperforming launches.