According to online reports, Qubic, a blockchain project led by IOTA co-founder Sergey Ivancheglo (CFB), has used the "Proof of Useful Work"(uPoW) mining method to control more than 20% of Monero's computing power, and plans to strive to master more than 51% of computing power from August 2 to 31 to demonstrate its technical strength. Qubic quickly amassed a large amount of computing power by rewarding miners to participate in Monroe CPU mining. At the same time, it used Monero coins obtained from mining to exchange stable coins to support the repurchase and destruction of its own tokens and create an economic incentive mechanism. The move raised serious concerns in the Monroe community about network decentralization and security. If Qubic controls more than half of the computing power, it may reject valid blocks from other mining pools, resulting in isolated blocks and transaction delays, which seriously affects the normal operation of the network. Qubic plans to stop publishing computing power data from August 2, intended to alert the public to the risk of a 51% attack. Analysts pointed out that Monroe spends about US$130,000 a day on network security, but it only needs to invest US$7000 to US$10,000 a day to gain control over most of its computing power, exposing the Proof-of-Work (PoW) network's potential weaknesses in the incentive mechanism. This incident is not only a crisis facing Monroe, but also a wake-up call for all PoW blockchains.