More than a quarter century after Nintendo and Sony’s efforts to team up to create a joint video game console collapsed, one of the prototypes of that failed partnership is going up for auction. And it may set an all-time high score for classic video game memorabilia.

Heritage Auctions has included the Nintendo Play Station Super NES CD-ROM Prototype (Nintendo Play Station for short) as part of an upcoming auction in Dallas. Pre-bidding for the system has already hit $280,000, with more than a week left before collectors will have a chance to escalate the price in a live auction on March 6.

And even Heritage Auctions officials say they’re unable to guess how high bids will eventually go. “I think it’s safe to say this prototype has already exceeded our expectations,” Valarie McLeckie, the auction house's consignment director of video games tells Fortune. “There are a lot of rumors circulating about where the price will end up once the hammer falls."

The Nintendo Play Station came about in the early 90s. The two companies collaborated to create a machine that would play games on both Super Famicon cartridges as well as CD-ROM.

As the prototype got close to production, the gaming giants got into a contract dispute. Nintendo opted instead to partner with Philips for a CD drive for the SNES (Super Nintendo Entertainment System). Sony proceeded on its own, eventually releasing the PlayStation (one word) that went on to be a sensation(but didn’t play cartridge games) in 1994.

All of the prototypes for the Nintendo Play Station were thought to be destroyed.

The Nintendo Play Station is currently owned by Terry Diebold, who bought the prototype for $75, as part of a lot during a bankruptcy auction of Advanta Corp., where he worked as the company's facilities maintenance manager. Advanta was run by Olaf Olafsson, a former president of Sony Interactive Entertainment, who apparently kept one of the prototypes of the system he helped create.

Diebold’s son found the device in the family attic in 2015, and they have regularly taken it to exhibits and conventions over the past five years. Recently, though, Diebold decided to sell the rare item.

Now that the prototype is becoming available for sale, it’s attracting some high profile bidders, including Palmer Luckey, creator of the Oculus Rift.

“I am on a quest to digitize and preserve the history of physical videogames,” Luckey said on Twitter. “Perfect VR will ensure the original experience lives on forever, but we need to keep these things alive and functional in the meanwhile.”

The Play Station is also likely on the radar of Eric Naierman, a dentist and one of the world’s most avid video game collectors, who last year spent more than $1 million on a 40 title collection that includes ultra-rare, sticker-sealed games.

Heritage Auctions' online bids are posted immediately, but the buyers are promptly vetted by the company. If they’re found incapable of backing up their bids, the previous high bid is reinstated. (That’s why the auction’s price has fallen from higher bids, some of which have exceeded $400,000.)

Bidders are responsible not only for their bid price, but also a 20% sellers fee on all lots, which bumps the $300,000 bid up to a $336,000 price.

While the Nintendo Play Station is certainly the marquis item in the Heritage auction, it’s not the only thing that has collectors salivating. An extraordinarily rare copy of Bandai’s Stadium Events is also up for bids, which so far, have hit $45,000. The title that was one of the video game industry’s first exercise games, but was recalled soon after its 1987 release, and there are only 200 known copies of the game are in existence. This copy of Stadium Events is in the best condition of any to ever go up for auction, and has an 9.2 rating from Wata, an independent assessment service that specializes in video games. McLeckie says another copy of the game, with a 6.0 rating, sold for $11,700 last November. And an unboxed version of the game, with a 4.5 rating, sold for $10,000 in February 2019.

“The game has commanded a pretty significant premium in the past,” she says. “When it comes to video game collectors, condition is pretty much everything at this point.”