Cryptocurrency has become a global phenomenon in recent years, attracting investors from all walks of life.As the oldest and most popular cryptocurrency, Bitcoin in particular has been embraced by some of the most powerful and successful corporations in the world, including Tesla, Square and Facebook.Critics, meanwhile, say crypto is volatile, bad for the environment, unsafe, and an all-around unwise investment.But, more importantly, is crypto a bubble waiting to burst? It absolutely is, according to one renowned expert. Read more below.Crypto BubbleIn an interview with Yahoo Finance, financial adviser Ryan Payne said that Bitcoin, and cryptocurrency is general, is one of the biggest bubbles in history."This whole Bitcoin thing -- this whole cryptocurrency -- is one of the biggest bubbles ever. I do think that bubble is eventually going to burst. It's going to be ugly," said Payne, who is the president of Payne Capital Management.Over the weekend, as Yahoo Finance noted, Bitcoin dropped to below $50,000, even though many investors expected it to hit $100,000 by the end of this year.Dot-Com BubbleAccording to Payne, what's happening in crypto world right now is reminiscent of the 1990s dot-com bubble, which was caused by excessive speculation of Internet-related companies and resulted in the destruction of dozens of large, profitable companies.As Payne explained, the cryptocurrency market is worth around $2 trillion, while dot-com stocks were worth half of that."When the dot-com bubble burst, those dot-com stocks where worth like half a billion dollars. Inflation adjusted that's like $1 trillion in today's dollars. Most of those stocks became worthless," he said.Bitcoin Will Keep Surging, Payne SaysPayne added that he expects Bitcoin to keep going higher due to excess liquidity, but that's not necessarily a good thing."There's too much money out there that can funnel into this market. it's just becoming a bigger and bigger casino. At the end of the day we're not using it for that much more commercial use. It's just more people speculating and I think it's very analogous to when the tech bubble burst, or you go back to the housing bubble ... where everybody's involved."Investing In CryptoAccording to Financial Times, experts and investors are divided on crypto, with some calling it a great opportunity and others describing it as a waste of time.According to research from broker Charles Schwab, young people -- millennial and Gen Z investors -- are far more likely to buy cryptocurrencies than equities.A survey conducted by Schwab shows that, in contrast, just eight percent of investors aged 55 or older trade digital currencies.Other research shows investors have lost more than $16 billion in crypto-related fraud since 2012.