This mischief-maker is out to prove that blockchain is not as secure as crypto-enthusiasts say it is.

Look out for a message saying Einsteinium has been hacked and double-spent with all the details. Cross your heart and hope to die. That’s a Reddit user‘s promise. He’s been offered $800 to fulfill his bet.

“Hey all,” someone called team-periwinkle told his Reddit team, “On Oct 13, 3:00 CDT, 4:00 EDT 1:00 PST I’m going to do a 51% attack against the cryptocurrency Einsteinium. I’m putting in $50 of my money and if you want to donate you can.”

The hacker, also called @geocold51 on Twitter, told Reddit he’ll be live-streaming his performance on Twitch so viewers can catch him in the act.