Demogorgons are mythical creatures, that may be presented as demons or higher beings, and likely originated with Greek mythology. The earliest known reference to a demogorgon is in the Latin poem The Thebaid, which is a twelve book cycle by Publius Papinius Statius. It has also been referenced in other notable texts including John Milton's Paradise Lost, and Herman Melville's Moby-Dick.
The concept of a demogorgon has also been represented in the roleplaying game Dungeons & Dragons. This version of a demogorgon was the inspiration behind a type of interdimensional predatory creature featured in the Netflix original series Stranger Things. In the show, Demogorgons hail from an other-dimensional reality that has been called the Upside Down. A demogorgon is a tall, slender bipedal being with a quasi-humanoid physique save for its head, which includes a sectional mandible that opens up like flower petal forming four distinctive "lips" as it were. Demogorgons are not a sentient species, and behave more like an animal. It is believed that they are part of a collective consciousness that obeys the whims of a more powerful creature dubbed the Mind Flayer. The demogorgans may be parasitic in nature, as it has been show that they're young may nest inside of a human host. Its birth cycle is similar to that of a pollywog, or tadpole, but it grows quickly, and can sustain itself on just about anything, though clearly it has a predilection towards consuming flesh.