Hikers in Ireland were strolling among the frosty trees last week when they stumbled into what looked like an enchanted candy forest. White wisps of fluffy frost bloomed from tree branches like cotton candy, but the mysterious fluff disappeared with a single touch, the hikers tweeted.

There’s no witchcraft afoot in the forest (and no, the hikers were not named Hansel and Gretel), but there is some minor alchemy happening, thanks to a peculiar and productive fungus. This bizarre winter phenomenon is known as “hair ice,” named for the fine, 0.007-inch-wide (0.2 millimeters) strands of ice crystals that appear to grow out of certain trees in freezing temperatures.