Mule
A Mule is not a Horse..... but it is not a Donkey........ No, the humble Mule is a much more sinister beast, born of the two factions.

Mules are animals known for their strength, resilience, minimum of four legs, abnormal levels of gamma radiation, and intelligence.
They are real animals.[citation needed]
If you see a mule, do not look it in the eyes, and immediately evacuate the area. The forbidden mule's sinister aura will affect you negatively. Mules are also highly venomous. Woah!
Origins
Mules were invented in the year 1989. Jimmy Muleman thought it was a good idea to crossbreed his horse and his donkey. It wasn't, and he was wrong.
He was completely unaware of the evil he had unleashed unto the world until much later, after he had constructed a mule factory to create many more mules. His 10043rd mule had impersonated him for several years, doing horrible deeds and malicious acts under his name, which negatively affected Muleman's credit score and reputation even after the investigation in 1995 uncovered the identity of the mule. In 1999, after a long, long trial, Jimmy Muleman was sentenced to a hundred years in the Poop Room for creating mules. Cowabunga, dude!
Uses
Due to their strength and smarts, the preposterous mule is often used in farming, as a method of transportation (for both people and items), and crime. Some treacherous mules have no use except for evil. This is because they are the most sinister mules. The most sinister mules are created when a horse and a donkey don't like each other and have no good qualities, yet still crossbreed with each other. Both animals turn into volcanic ash immediately after the most sinister mule is born. That's not good.