In August 2025, people on social media began describing a phenomenon that sounded like a horror movie turned into reality. "Experts Warn of Infected 'Frankenstein' Rabbits with Tentacles Invading the US. These wild rabbits have been spotted hopping around with nightmarish facial growths across Fort Collins, Colorado," claimed one X post (archived) with over 1 million views.
"MAJOR CONCERN... Rabbits spotted invading parts of the US with weird tentacles sprouting from their heads due to virus... Colorado officials are warning: 'DO NOT TOUCH,'" claimed another X post (archived) viewed nearly 8 million times. Another
Those posts were only the tip of the rumor-spreading iceberg. Outside of X, Instagram posts about the "invading" rabbits were liked nearly 100,000 times (archived), more than 45,000 times (archived) and more than 25,000 times (archived). A Facebook post (archived) about the supposed expert warning was reacted to over 10,000 times.
(X user @DailyLoud)
There is a real virus that infects rabbits with a disease whose symptoms include black growths on their skin (usually on the head) that look like tentacles or horns, Colorado Parks & Wildlife has reported. The virus goes by a few different names, such as Shope papilloma virus (SPV) and cottontail cutaneous papilloma virus, according to PetMD. However, the fear-mongering nature of the posts was entirely inaccurate. The virus has been in the U.S. for decades and cannot be transmitted to humans.
Usually, the growths have no significant effects on wild rabbits unless they prevent them from eating and drinking. According to the Smithsonian, this may happen if large enough growths develop near the rabbit's mouth. The growths go away after the infected rabbit overcomes the infection, however.
The disease is more severe in domesticated rabbits than in wild rabbits. That's because the growths can become malignant, cancerous tumors, which happens three times more often in domesticated rabbits than in wild rabbits, according to ScienceDirect. PetMD said the growths caused by the virus can be surgically removed by a veterinarian before they become malignant.
SPV is frequently seen in wild cottontail rabbits, but can be contagious to other breeds, including pet rabbits. The virus is specific to rabbits and does not cause disease in other species. It is most often spread by biting bugs such as ticks and mosquitoes. Outbreaks of the disease are most common in the summer and fall, when populations of disease-carrying bugs are at their highest.
The virus was first described in rabbits from Kansas and Iowa by Richard Shope, which is how it got one of its names in 1933, said a 2015 study published in the peer-reviewed journal PLoS One. According to the study, the virus is known to be found "almost exclusively" in the U.S. Midwest.
A U.S. Department of Agriculture (USDA) report from 2013
In summary...
There is a real virus that infects rabbits and causes growths that may look like tentacles or horns on their faces. The infection is exclusive to rabbits, so no warnings are needed except for rabbit owners, who should keep their rabbits inside and away from biting bugs when and where the virus is most common. It's not "invading" the United States, either; it was first discovered in the U.S. and is still most common in the U.S.
As for the "Frankenstein" part of the claim? The Smithsonian said sightings of the infected rabbits may have contributed to the legend of the antlered Jackalope, which it said is "also commonly known as a 'Frankenstein' rabbit."