Today, a large number of witches appeared in @ opensea, and there are different opinions on the reasons for the witches. On chain analysis. One is to check the wallet association, whether it transfers or shares the source of funds. The second is to analyze the trading mode, whether to purchase the same NFT or only participate in the same task. The third is to check the completion behavior. Whether to complete tasks with consistent amounts or at the same time. 2-Off chain detection. Monitor IP addresses and browser fingerprints to determine if multiple accounts are rolling over the network from the same device. 3. Abnormal behavior. Do you frequently disconnect and reconnect your wallet, constantly signing. What else? Did you split the IP address, fingerprint it, run it without a synchronizer or script, and communicate with the witch!