The play-to-earn game Axie Infinity features colorful NFT characters which gamers purchase to engage in battle with others. According to the NFT analytics site CryptoSlam, the game has recorded over $1.04 billion in all-time sales with over 2.4 million transactions. Players can initially purchase the digital pets, called Axies, using Ethereum with a Metamask crypto wallet. Ethereum is trading just over $3,100 on Monday morning.