From the article:
How does Ordinal sniping work?
Ordinal sniping is a type of front-running attack that exploits the mempool, a holding area for unconfirmed Bitcoin transactions. In Ordinals, sniping involves monitoring the mempool for valuable Ordinal transactions, such as minting rare or highly sought-after Ordinal NFTs and creating an allocation of a new token or trading an NFT or Token allocation with another user