3/6/2011
⛏️ Mysterious Miner
On March 6, 2011, Bitcoin hashrate briefly reached a new high of almost 900 Ghash/sec, but soon dropped to 500 Ghash/sec. Some attribute this spike to some supercomputer or botnet that joined the Bitcoin network (the mysterious miner).
Sources:
https://archive.bitcoin-calendar.org/archive/1749193030.746952/index.html
http://bitcoin.atspace.com/mysteryminer.html