  NFT rug pull is one of the most prominent type of scam that the developers of
a project abandon it and then run away with investors' funds. Although they
have drawn attention from our community, to the best of our knowledge, the NFT
rug pulls have not been systematically explored. To fill the void, this paper
presents the first in-depth study of NFT rug pulls. Specifically, we first
compile a list of 253 known NFT rug pulls as our initial ground truth, based on
which we perform a pilot study, highlighting the key symptoms of NFT rug pulls.
Then, we enforce a strict rule-based method to flag more rug pulled NFT
projects in the wild, and have labelled 7,487 NFT rug pulls as our extended
ground truth. Atop it, we have investigated the art of NFT rug pulls, with
kinds of tricks including explicit ones that are embedded with backdoors, and
implicit ones that manipulate the market. To release the expansion of the scam,
we further design a prediction model to proactively identify the potential rug
pull projects in an early stage ahead of the scam happens. We have implemented
a prototype system deployed in the real-world setting for over 5 months. Our
system has raised alarms for 7,821 NFT projects, by the time of this writing,
which can work as a whistle blower that pinpoints rug pull scams timely, thus
mitigating the impacts.
