Tom is an "Ethereum inscription concept coin" deployed on the Ethereum mainnet. The rules for subsequent minting are established by the first person who mints it.
Similar to Ordinals protocol on Bitcoin, Ethscriptions allow people to inscribe different types of files on the Ethereum mainnet, as long as the file size does not exceed 96KB. Specifically, the protocol records a memo (hexadecimal characters) in a transaction and then records it in a block.