Bitcoin's hashrate soared to an unprecedented 1,109 exahash per second (EH/s) on September 29, 2025, significantly bolstering the security of merge-mined chains such as Namecoin, Rootstock, and Fractal Bitcoin. This increase in computational power, facilitated by auxiliary proof-of-work (AuxPoW), allows miners to secure multiple blockchains simultaneously. Namecoin, Rootstock, and Fractal Bitcoin have all benefited from Bitcoin's overflow hashrate, achieving 786.98 EH/s, 822.92 EH/s, and 768.91 EH/s respectively. This development highlights the potential of merge mining to enhance security and scalability across various proof-of-work networks.