By Natalie DeCoste

What started as a joke is now becoming a successful cryptocurrency as Dogecoin’s value skyrocketed last week.

Dogecoin is a digital cryptocurrency like Bitcoin. Unlike Bitcoin, the product started as a joke based on the “Doge” meme, which rose to popularity in late 2013. The meme portrays a Shiba Inu dog with nonsensical phrases in colorful, Comic Sans-font text around it. The currency was created by software engineers Billy Markus and Jackson Palmer and was intended to be used as a faster but “fun” alternative to Bitcoin.

While Bitcoin has set 21 million coins as the limit on its currency, Dogecoin has 129 billion coins in circulation and will continue to make new blocks of coins available to mine each year. The greater number of coins explains the wide price difference between Dogecoin and Bitcoin.

Dogecoin may cost significantly less than Bitcoin, but the price of the meme currency is on a rapid ascent. The currency has a total market value of more than $40 billion. Out of that $40 billion, $20 billion was added between April 15 and April 16.

The total market value of the currency seems incredibly high, especially when considering that just one digital token reached an all-time high price of 32 cents Friday morning, which is more than double the price it was a day prior.

The spike even caused Robinhood’s crypto trading feature to go out of service for a short period. On Thursday, the popular U.S. online brokerage said there was a major outage in its crypto trading feature after facing “unprecedented demand.” Robinhood has since managed to bring the feature back online.

The massive price rise can be credited in part to Tesla founder Elon Musk and his ongoing support of the currency. On Friday, Musk tweeted out “Doge Barking at the Moon,” which many took as a reference to a phrase used by internet traders, “to the moon.”

This is not the first time Musk has come out in support of Dogecoin. In February, he tweeted saying the meme currency was his favorite cryptocurrency and that it was “The People’s Crypto.”

The price rally is also coinciding with the listing of Coinbase. The company is the most popular U.S. virtual currency exchange, and it just went public on Wednesday. The stock briefly hit a $100 billion market cap in what was a landmark moment for cryptocurrencies.

All the excitement over Coinbase led to general excitement in the cryptocurrency market. Bitcoin prices surged and hit a record high of more than $64,000 on Thursday. Other cryptocurrency ether briefly topped $2,500 for the first time Friday morning.

All of the price surges have led to concerns over a mounting cryptocurrency bubble that could very well burst.

“Dogecoin’s rise is a classic example of greater fool theory at play. People are buying the cryptocurrency, not because they think it has any meaningful value, but because they hope others will pile in, push the price up, and then they can sell off and make a quick buck. When everyone is doing this, the bubble eventually has to burst and you’re going to be left shortchanged if you don’t get out in time. And it’s almost impossible to say when that’s going to happen,” David Kimberley, an analyst at U.K. investing app Freetrade, told CNBC.