CryptoKitties is a blockchain-based game that allows players to collect, breed, and trade virtual cats. Each cat is a unique digital asset represented as a non-fungible token (NFT) on the Ethereum blockchain. Players can create new cats by combining the traits of their existing ones, leading to a variety of appearances and characteristics. Launched in November 2017, CryptoKitties gained significant popularity, causing congestion on the Ethereum network due to high transaction volumes. The game highlights the potential of NFTs and has inspired various other projects in the growing field of digital collectibles and blockchain gaming.