A new outbreak came to your local town, and became very dangerous as it corrupts both the body, and the mind of a human being. This disease, simply known as the Taur Virus, causes the victim to become half animal, and make them sexually aroused, while sometimes even changing their gender anatomy.
Most of the time, the Taur Virus makes the victim half horse, and half human, while giving them an extra set of legs. The genitals move closer to your butthole, and become more animalistic, while the lower half of the human has their feet change to match the new ones, while fur covers the entire lower half. Many are able to avoid the effect of the Taur-Virus, as long as they stay away from areas that have ominous green fog, while having sex with their romantic partners near any animal.