In October, I tried my hand at an early version of CryptoKitties, a game in which players breed digital cats on the Ethereum blockchain by executing smart contracts. At the time, it seemed would be a fun (and short-lived) way to introduce newbies to the way smart contracts work on the Ethereum network.

But when CryptoKitties was officially released on October 28, it unexpectedly became a multi-million dollar digital kitten mill—perhaps the strongest ever confirmation that a fool and their Ethereum are easily parted.

At the time of writing, CryptoKitties is the busiest smart contract on the blockchain, accounting for a little over 11 percent of all network traffic.

As TechCrunch put it, “we now have people using Ether, an asset with arguably little tangible utility to purchase an asset with unarguably zero tangible utility.” Still, CryptoKitties is the closest thing to a "killer app" to be released so far on the Ethereum network, which has mostly been used to fund sketchy multi-million dollar investment rounds for applications that don’t exist.

Over the weekend, over $2.5 million (about 6,200 ether) passed through this smart contract as a result of people breeding, buying and selling these digital kittens.

The most expensive kitten, Genesis, sold for nearly $118,000 on Saturday, according to a third-party website keeping track of Cryptokitty sales. The average price of a Cryptokitty is about $110 and the cheapest cat is about $30. Tales of people making hundreds of dollars on digital cat sales are already cropping up in the Cryptokitties subreddit.

The Cryptokitty craze has rightfully drawn comparisons to the Beanie Baby bonanza of the late 90s, an impressive feat for a game that emerged from an Ethereum hackathon in Toronto just a few months ago.