Homer's Spirit Guide (also referred to as "The Space Coyote" or Johnny) is a talking coyote whom Homer meets in a chili-induced hallucination. Homer called him "Wolfy".
History
Homer follows the Tortoise to a pyramidal structure which then grows to an enormous height, and he has to climb it. At the top of the pyramid, Homer sees a pair of eyes appear in the sky out of the moon and a planet, and then it manifests as the coyote. The coyote introduces himself as Homer's Spirit Guide, and tells Homer to find his soul mate. Shortly after that, Homer wakes up.
Homer later hears the voice of the Spirit Guide again, telling him to find his soul mate. When Homer asks for an explanation, the Spirit Guide says that he can't tell Homer any new information as he's only his memory.
The Spirit Guide makes a small, non-speaking cameo in "Blazed and Confused" during Marge's hallucination.
The Spirit Guide also appeared in the Simpsons comic story "Chili Chili Bang Bang" when he talked to Wiggle Puppy, Clancy Wiggum's spirit guide.
Appearances
Episode – "El Viaje Misterioso de Nuestro Jomer (The Mysterious Voyage of Homer)" 
Episode – "Blazed and Confused" - Comic book – The Simpsons Summer Shindig #2 - Chili Chili Bang Bang
Video game – LEGO Dimensions (Homer Level Pack)
Video game – The Simpsons: Tapped Out