Over the past several days, the share prices of three companies have surged 25% or more in a single trading session. Those companies are Krispy Kreme, GoPro, and Kohl’s. Yet none of these firms have made any major announcements of late that support such lofty rises in their stock prices. So why are their share prices skyrocketing? It looks like meme stock mania is back. What is a meme stock? The term “meme stock” first gained popularity during the early pandemic years. During the 2020-2021 period, many people were confined indoors due to lockdowns or a general fear of going out, so they turned to the internet to pass the time, often taking on new digital hobbies or joining new communities. For many, a new hobby emerged: online investing. As a result, many of these new investors turned to social media for advice on which stocks to buy. Perhaps the most popular social media community for stock advice was the Reddit forum r/wallstreetbets, and it is in this community where many consider meme stock mania to have originated. A meme stock is generally defined as a stock that is promoted by members of an online community, such as the one found in the r/wallstreetbets subreddit. Proponents of a meme stock buy shares of a stock at a low price—often in struggling companies with some brand name awareness—and then promote it, attempting to build hype and a positive narrative about the stock, as noted by Investopedia. The goal is to get in on the meme stock while the price is low, see the value surge as more people who are afraid of missing out on a 10x or 100x bagger buy into the stock, and then often to get out of the stock before the hype collapses and the shares crash again. As Reuters points out, meme stocks are often heavily shorted. The rise in share prices for these stocks force investors who had bet against the stock to sell their shares to limit their losses. In the early pandemic years, two of the most popular meme stocks were the struggling video game retailer GameStop Corp. (NYSE: GME) and movie theater chain AMC Entertainment Holdings, Inc. (NYSE: AMC). But now, as of this week, there’s a new trio of meme stocks sending a frenzy through online trading communities. Krispy Kreme Probably the most well-known meme stock among the new trio is Krispy Kreme (Nasdaq: DNUT), the donut company that loves giving away tasty treats. Over the past day or so, people have been talking up DNUT stock on social media, and as a result, Krispy Kreme shares have surged. Yesterday, Krispy Kreme’s stock price jumped a staggering 26% in a single trading session. DNUT stock went up 87 cents per share to close at $4.13. And today the stock is surging again in premarket trading, as of the time of this writing. DNUT shares are currently up another 25%. GoPro Another moderately well-known brand name is also the newest meme stock. GoPro, Inc. (Nasdaq: GPRO), maker of the tiny portable cameras that are popular with extreme sports enthusiasts, saw its shares blast off yesterday.  In Tuesday’s trading session, GPRO shares leaped an asounting 41%. The company’s stock price went up 39 cents per share to $1.37 by market close. And today, GPRO stock is trending even higher. As of the time of this writing, in premarket trading, GoPro shares are up another 56% to $2.14 per share. Kohl’s The third meme stock in this latest trinity is Kohl’s Corporation (NYSE: KSS). The clothing retailer’s shares jumped a massive 37% yesterday in a single trading session. During the period, KSS shares climbed $3.92 to $14.34. The volatility led to trading being temporarily halted, as CNBC reported. But as of premarket trading this morning, KSS shares aren’t having continued gains. The stock is currently trading flat in premarket, according to data from Yahoo Finance. Fast Company reached out to Krispy Kreme, GoPro, and Kohl’s for comment. A cautionary tale It’s hard not to see single-day gains of 25% to 50% in a stock and not feel the urge to buy in. However, most financial advisors would advise against buying into a meme stock as they are considered a relatively high-risk investment. That’s because meme stocks see their prices surge due to the hype online communities build up around that stock, not due to any firm fundamentals of the company itself. This online hype often leads many to buy into the stock, causing its price to surge.  But if the fundamentals of a company do not support the stock’s price, the stock will most likely crash, and investors who got in at the wrong time could see their entire investment washed away. Take one of the most popular meme stocks in history, for example. People went crazy for AMC Entertainment Holdings, Inc. (NYSE: AMC) in December 2020. That month, the stock was trading for around a low of $20, according to Yahoo Finance data. But then meme mania bit, and by June 2021, AMC shares were over $566 each.  Yet by the next month, AMC shares had