The creator of the wildly popular Nyan Cat GIF decided to celebrate its 10-year anniversary by selling a digital asset known as an NFT—a non-fungible token—at auction. The sale, hosted by the new NFT marketplace Foundation, pulled in a whopping 300ETH—that’s for the blockchain called Ethereum—or the USD equivalent of roughly $561,000.

The price shot up in the final 30 minutes of bidding from 15ETH (roughly $18,000), after having started around 3ETH ($5,000).

“It was crazy,” the artist, Chris Torres, told Artnet News. “At first the auction was going very slow, so I didn’t think it’d get that many bids, but there was a wild bidding war near the end. Part of me was thinking, this can’t be real. There’s no way.”

So what exactly is Nyan Cat? The pixelated gray cat is a throwback to 1980s video game characters seen in Pac-Man or Atari. It flies in a straight line through an equally dated-looking starry night backdrop, a stream of rainbow colors trailing behind. All of this is set to a relentlessly chirpy techno soundtrack. The three-minute-plus video uploaded to YouTube in 2011 spawned dozens of memes after, including a 10-hour video of Nyan Cat on repeat, and one featuring 50 different cat memes that all riff on the original cat. Nevertheless, the NFT for the work is unique, Torres noted.

“Thanks for believing in Nyan Cat all these years,” Torres said in a tweet after the sale. “I hope this inspires future artists to get into the #NFT universe so they can get proper recognition for their work.”

Christie’s recently announced the sale of its first-ever purely digital artwork at auction: Everydays—The First 5000 Days by Mike Winkelmann, who goes by the name Beeple. It will be offered in a standalone online sale aimed at new and younger collectors.

Like Torres’s Nyan Cat, Beeple’s work carries an NFT, a unique digital token encrypted with the artist’s signature and individually identified on a blockchain, effectively verifying the rightful owner and authenticity of the creation. In December, the first large-scale auction of Beeple’s art grossed $3.5 million in a single weekend, according to Esquire, which offers newbies a good in-depth primer on how NFTs work.

For the 10th anniversary of his GIF, Torres said he created a remastered version of the original, which includes a series of tweaks. For instance, a star that would appear randomly in the original 12-frame animation reportedly irked him, so he removed it for the remastered edition.

As the bidding neared its end, Torres and a representative for Foundation watched the action on a Twitch video, which was shared to Twitter. “I love cats and I love bright colors,” Torres said as he talked about the “LOL Comics” series of stick figure characters he’s been producing for the past 20 years.

Foundation launched as an NFT marketplace earlier this month and hit $1 million in sales within its first two weeks. 

On Foundation, artists set a reserve price; once it’s met, it triggers a 24-hour auction. If a bid is placed within the final 15 minutes, it extends the auction another 15 minutes. At the Nyan Cat auction, there were 29 bids placed and the majority of those happened within the final hour, so the sale kept getting extended.

“The sale is significant because it’s the first famous meme to sell as an NFT,” said Foundation’s head of community Lindsay Howard, “and it signals a new era where digital artists can be directly compensated for the work they create and share online.”

Torres agreed, saying the best part about the NFT world is that “it’s a way for artists to directly monetize off their hard work.”