In late 2018, a game called CryptoKitties debuted and generated more than $1.3 million in transactions of virtual cats in just over a month. A studio called AxiomZen created the phenomenon, powered by the Ethereum cryptocurrency blockchain, and on Dec. 3, 2017, TechCrunch reported that the price of one CyrptoKitty ranged from the equivalent of roughly $12 to $113,000.

Cat breeding also occurs in the game, which influences pricing. As of Jan. 22, 2018, there have been 268,341 sales of CryptoKitties and 210,469 unique kitties sold, with sales totaling $19,160,337. Axiom takes a cut.

Related: 3 Things Entrepreneurs Need to Understand About Blockchain Technology

The publication compared the craze to Beanie Babies in the 1990s, as well as Neopets, but made the distinction that because no centralized entity owns or manages CyrptoKitties — those who own them will have access to them forever, even if they don’t have much value down the line.

The game’s complicated, but you can read the FAQ here.

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