The rabbits – also nicknamed “Frankenstein bunnies” – with their bizarre “horns” were once the stuff of ancient folklore.

Wildlife officials in Colorado are monitoring an unusual increase in cases of Shope papillomavirus, a disease affecting wild and domestic rabbits, following a higher number of sightings this summer.

HORRIFYING images of ‘zombie’ rabbits with tentacles sprouting out of their heads have been circulating online – so is your pet bunny safe? The traumatising snaps have led to

CPW spokesperson Kara Van Hoose told KDVR: "There’s no overt concern needed for pet owners. We would just say to keep those wildlife principles in mind when you do have them out: Keep them on leash, keep them away from wild animals just in case, but it is not something necessarily we see transferred from rabbits to dogs.”

It's the cottontail papilloma virus (CRPV) at work - giving rise to the 'jackalope' myth (rabbit with antlers) in modern times - which causes benign, Lovecraftian tumours to materialise on the head of the animals.