Mountain Lion
The Mountain Lion is a legendary animal seen in Season Eight episode "Woodland Critter Christmas".
Background
In "Woodland Critter Christmas", Stan is forced into looking for and killing the mountain lion that the Woodland Critters say keeps eating the virgin critter every Christmas. Stan tricks the lion into falling off a cliff. After Stan kills the lion, Three Cubs walk up to her body begging for her not to leave them and begin to cry. Stan realizes what he had done and feels extremely guilty.
Later it is discovered that the critters' "savior" is the Anti-Christ, the Son of Satan, and is using Kyle as a vessel. However, with the help of the lion cubs, they carry out an abortion on Kyle, removing the Anti-Christ which is destroyed by Santa Claus. Santa then goes to the mountain lions' lair and brings their mother back to life. The cubs are happy at the end with their mother being alive once more and Stan goes home for Christmas.