Windchester (otherwise known by Michael Barrett as Sparkplug) is a black horse who kept following Michael around in the episode Quinn Misses the Mark. Michael found Windchester when he was angered by Logan and set his basket of cookies down that he was supposed to deliver to him. He then walked away from the cookies. When Michael turned around, to his surprise, an unknown horse spontaneously showed and and at his cookies. When he tried to make the horse go away, Windchester snorted and Michael ran away, screaming.Michael then seeked to prove that the horse was real. He lured it with a cookie right to Logan, to his surprise. After Michael proved to Logan that he was real, he told him to go back to wherever he came from. Windchester neighs and wants to eat Michael's cookie instead. Michael gives him the cookie and walks away.
Windchester was apparently originaly from a farm down south. In the end of the episode, a woman named Faye Dobson appears. She finds Windchester and says that her husband forgot to lock the gate, and he escaped the weekend prior to the events of the episode.
Michael fed Windchester cookies. Horses cannot eat cookies, but it appeared that Windchester liked them.