CriptoKitties is a game which was developed by the American-Canadian studio AxiomZen and which was launched on November 28, 2017 on the Ethereum blockchain. In this game, which is a cross between Tamagotchi and Pokémon, the user must collect virtual cats. It has already generated several million dollars and more than 15% of Ethereum network transactions are devoted to exchanges between users, it's completely crazy.
The principle of the game is to breed digital kittens. Each cat is one of a kind and has its own characteristics. The user is the 100% owner of his little virtual creature, which can in no case be copied or destroyed. It is possible to buy, exchange or sell CriptoKitties in the same way as a traditional collector's item or a cryptocurrency. Transactions are secure and ownership is acquired for life (because decentralized on the blockchain), as if you were storing an ether in your personal wallet.