"if not, I will eat my dick on national television." https://twitter.com/officialmcafee/status/887024683379544065

There's a longbets.org joke in this.

I'm guessing he would buy a single coin for $500k in 2020, rather than take the bet loss.

He doesn't even have to buy a single coin. He can just buy a fraction for $500,000 if you want to be technical.

I'd sell calls with a $500K strike price all day.

Name your expiration and ask. Cheap enough, it's worth the gamble!