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.

Viral photos have inspired a fluffle of unflattering nicknames, including "Frankenstein bunnies," "demon rabbits" and "zombie rabbits."

Rabbits with black, tentacle-like growths sprouting from their faces have been spotted in Colorado. Colorado Parks and Wildlife (CPW) said a viral infection called the cottontail rabbit papillomavirus caused the black growths on the rabbits.