The unknown attacker has promised to gain majority hashrate control of an altcoin to show how smooth the process is. They have given decent warning of the attack but promised to live stream the whole event on October 13, 2018, 3:00 CDT.
51% attacks, in which a malicious attacker assumes majority control of a digital currency's hashrate to greatly increase his chance of falsely double spending transactions, have largely been a frequently recurring theme this year. In a period of 90 days, a number of Altcoins were 51% attacked. Again, einsteinium (EMC2), a scrypt-based coin, is now the center of attention after being selected for an attack. See more for yourself
here.