“ ‘It feels kind of like voodoo economics and the price of the token isn’t really backed by anything. That’s a very spooky thing.’ ”

Sure, coming from any number of bitcoin BTCUSD, -1.58% critics, those comments would be expected. But coming from the guy who invented the second most valuable crypto before he even turned 20 years old?

Vitalik Buterin, Ethereum’s co-founder, recently told developers that he’s “concerned a lot of these token models aren’t going to be sustainable,” according to Bloomberg.