The growths are most likely caused by a summertime virus common in some U.S. states, but wildlife officials say there is no risk of transmission to humans or other animals.

Though the horned rabbits aren’t a danger to humans or pets, Van Hoose advises people to keep their distance from the creatures, as they should with any wild animal, because rabbits can pass along other pathogens. “Once you realize these probably aren’t harmful to rabbits, you can kind of appreciate the science at work,” she says.

Photos of the cottontails inspired nicknames like “Frankenstein bunnies,” “demon rabbits” and “zombie rabbits.”