As weird and concerning as they appear, the virus that causes the dark, wart-like horns or tentacles to grow on cottontail rabbits is relatively common and usually not anything to worry about, CPW

Wild rabbits in Fort Collins with tentacle-like growths are infected by a virus called Shope papilloma virus, often mistaken for the mythical jackalope.

FORT COLLINS, Colo. — Rabbits that look like something out of a nightmare are being seen in Colorado. Bunnies with what appear to be tentacles growing from their faces are hopping around Fort Collins, KUSA reported. One person described the rabbit as having “a scabbiesh-looking growth over their face.” https://t.co/fkeN8gW3vO