Top venture capitalist Jason Calacanis has not been a bitcoin booster and said there's a 33 percent chance the cryptocurrency goes to zero.
"Cryptocurrency is a real technology. It's fascinating. It's got the potential to do some amazing things," Calacanis told CNBC's "Squawk Alley" on Wednesday. "But we're talking about an unregulated, highly manipulated and anonymous global stock market."
Bitcoin lost a quarter of its value this month, briefly dropping below $10,000.
Calacanis argued much of the initial run that sent prices skyrocketing was manufactured through duplicate bitcoin wallets, giving the appearance more investors had bet on bitcoin.
Once casual investors realize they've been buying into "what is essentially a huge fraud," Calacanis said, the cryptocurrency will tank.
"Now that doesn't mean that people can't have fun," he said. But "what's happening right now is extremely dangerous."
Calacanis also pushed back on recent anti-tech sentiments emerging in both Washington and in broader U.S. society. In particular, he called out Salesforce CEO Marc Benioff, who earlier this week said Facebook ought to be regulated like tobacco companies.
"Benioff is being a little hyperbolic with the cigarette analogy. I don't think social media's going to take five or 10 years off people's lives," Calacanis said. "It's not lung cancer."