Venture capitalist Peter Thiel had some predictions about the future of cryptocurrencies, but he identified an obstacle to its ascent; billionaire Warren Buffett.

On Thursday, Thiel, who made his fortune in Silicon Valley and remains an active investor, singled out Buffett as a member of the financial "gerontocracy" of old elites, who have not been particularly bullish about cryptocurrencies' investability.

“Enemy No. 1 is the sociopathic grandpa from Omaha," Thiel blared to a crowd in Miami. Buffett's conglomerate Berkshire Hathaway is based in Omaha, Nebraska.

Why Thiel singled out Buffett came down to his past dismissal of cryptocurrencies. In 2018, Buffett referred to bitcoin in particular as “rat poison squared” and lambasted cryptocurrencies as “just dementia.”

“In terms of cryptocurrencies, generally, I can say with almost certainty that they will come to a bad ending," said Buffett in an interview with CNBC. "If I could buy a five-year put on every one of the cryptocurrencies, I’d be glad to do it but I would never short a dime’s worth.”

But Buffett has also warmed somewhat on cryptocurrencies. Earlier this year, Buffett disclosed that he invested $1 billion in NuBank, a Brazil-based bank that has gained popularity among cryptocurrency holders.

But Buffett was not the only member of the “gerontocracy” that Thiel felt was blocking the ascent of cryptocurrency. He also directed criticism at JP Morgan’s CEO Jamie Dimon and BlackRock’s Larry Fink for their stances on the digital asset.

Dimon, said Thiel, possessed the “New York City banker bias” for his dismissal of bitcoin and other cryptocurrencies. Fink was also added to Thiel’s “enemies” list of bitcoin skeptics.

Despite any past skepticism, both Dimon and Fink have signaled that they have warmed somewhat to cryptocurrencies and the blockchain technologies that they rely on. JP Morgan has even moved in the direction of creating its own cryptocurrency under Dimon’s tenure. Fink has also spoken about the potential for cryptocurrency systems in his most recent letter to shareholders.