The owner of the Grumpy Cat NFT can do one better, he could flash loan his NFT at a small cost. Simplified you can think of an NFT being the following tuple: (

The owner of the Grumpy Cat NFT can do one better, he could flash loan his NFT at a small cost. Simplified you can think of an NFT being the following tuple: (NFT contract address, public address). Uniqueness of this tuple is guarenteed by the EVM and liveness of this information is guaranteed by the Ethereum blockchain. A lot of the NFTs value derives from the popularity of the individual that holds the private address corresponding to the public key that created the NFT contract. This is the implicit way it represents the original Grumpy Cat and is not something you can duplicate seeing as you're not Tabatha Bundesen.