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

The cottontails recently are infected with the mostly harmless Shope papillomavirus, which causes wart-like growths that protrude from their faces like metastasizing horns.

Colorado Parks and Wildlife say rabbits in Fort Collins are infected with rabbit papilloma virus, causing horn- or tentacle-like growths.