The Oenpelli python, known in binomial nomenclature as Simalia oenpelliensis, formerly Morelia oenpelliensis, is a species of large snake in the family Pythonidae. The species is endemic to the sandstone massif area of the western Arnhem Land region in the Northern Territory of Australia. There are no subspecies that are recognised as being valid. It has been called the rarest python in the world. Two notable characteristics of the species are the unusually large size of its eggs and its ability to change colour.