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

Rabbits with black, hornlike spikes growing on their heads and other odd or unslightly protuberances are not dangerous and won't infect humans or other species, Colorado Parks and Wildlife said Wednesday, following days of social media posts about sightings of "Frankenstein bunnies," "demon rabbits" and "zombie rabbits" in and around Fort Collins.

Colorado Parks and Wildlife: Scary-looking rabbits were hopping around Fort Collins. These weren’t your standard cute, fluffy bunnies; they had horn-like growths protruding from their faces and bodies.