Have you heard of cotton candy grapes? They’re a magical (but actually real) grape that somehow tastes exactly like your favorite sticky, sugary, carnival candy, and they’re pretty hard to find. But now, and for only a limited time, Sam’s Club is selling cotton candy grapes. Because the grapes are a bit of a novelty (they’re only in season for about a month in late summer), they’ll probably sell fast, but if there’s a Sam’s Club near you, it’s worth it to seek them out. Otherwise, you’re stuck waiting until this time next year to see what the hype is all about.

For everyone who’s wondering: no, cotton candy grapes are not a product of nature. The grapes were developed by a team of scientists at the International Fruit Genetics in Bakersfield, California, led by horticulturist David Cain. The grapes were created by growing a hybrid of two different types of grapes, NPR reported in 2013. Unlike the green grapes typically sold at the grocery store, cotton candy grapes aren’t tart at all, Cain told NPR, and even have a have a slight vanilla flavor. The sweet fruit contains about 12 percent more sugar than your typical grape. Think of it more like candy on a vine.

Cotton candy grapes are distributed through Grapery, which grows several other mad scientist grape flavors. After cotton candy grape season is over in September, Grapery promises Moon Drop grapes, Flavor Pop grapes, and Gum Drop grapes, according to the company website.

If this Franken-grape sounds tasty, there’s a window of a few weeks where Sam’s Club will be in stock. According to Cosmo, there should be enough grapes to meet customer demand for about three or four weeks. The store is selling the grapes in three-pound bags, so be sure to prime your sweet tooth!