First it happened to verge. $ 1.8m of cryptocurrency swiped in a matter of hours. Then to bitcoin gold, plundered in an $ 18m double spend attack. Then to verge again, this time to the tune of $ 1.7 million. Along the way, monacoin is also believed to have been hit. Someone is methodically working their way through Proof of Work coins, controlling their hashrate, and then launching 51% attacks. Other PoW teams are now on high alert for signs that their coin could be next.