1.POP:Proof Of Play, POP is an open source NFT protocol based on erc-721.
2.POP aims to create a reliable new way to record game experience. As long as players participate in a game and complete certain campaigns, they will receive a unique badge on the blockchain as a souvenir.
3.POP modified erc-721 so that it will always follow the player's address from casting, and can not be traded and transferred.