Demogorgon

The Demogorgon is a species of grotesque creature from a parallel dimension known as the Upside Down.

Biology
Demogorgons are mostly humanoid in stature and body shape but with thin, fleshy skin with visible bones. Some body parts, such as their arms, legs, fingers, etc. are more elongated, making them appear taller than a normal human. One of the more noticeable aspects of the Demogorgon is its massive gaping mouth with circular rows of teeth and several jaws that, when together, resemble the shape of a butterfly or flower.

Appearance
The Demogorgon has roughly six stage in its evolutionarily lifecycle from larvae to pollywogs etc. and eventually will became fully grown adults.

Stage One
While in stage one, Demogorgons resemble a garden slug, with dark brownish-green coloration marked with bright yellow spots. The larvae can inhabit human bodies, weather dead or alive, as they're known to have infected victims such as Will Byers and Barb Holland.

Stage Two
The second stage resembles an oversized terrestrial tadpole with merely a pair of front legs.

Stage Three
By the third stage, it has developed hind legs, thus becoming a quadruped.

Stage Four
The fourth stage becomes considerably larger and more dog-like, no longer crawling but instead walking. It also develops its characteristic multi-part mandibles which opens up like a flower.

Stage Five
The fifth stage has been nicknamed "Demodog" and increases in size considerably, being now comparable to a wolf in both physical shape and behavior, as they are known to form packs. Unlike wolves, however, they are also excellent tunnellers.

Stage Six
Upon the sixth and apparent final stage they have now grown to plantigrade humanoid bipeds and completely loose their tail. Adult Demogorgons are substantially stronger and is enable to travel through dimensions randomly.

Abilities
The Demogorgon has the ability to travel to and from Earth and the Upside Down by using rifts that it is able to create. Much like the other creatures of the Upside Down, the Demogorgon has a sort of hive mind connection with the denizens of the Upside Down, such as the Mind Flayer, Demobats, and the fungal and flesh-like environment that it inhabits.

Hunting Methods
Since the Demogorgon is non-sapient, it mainly acts as more of an animal than a sentient creature. The way the Demogorgon hunts down its victims on Earth is reminiscent of how a shark hunts its prey. Like a shark, the Demogorgon can detect blood on Earth despite currently being in the Upside Down, once he detects the blood, it then travels to Earth and take its victim to the Upside Down where the Demogorgon will either eat its prey or impregnate it with it's larvae by keeping its victim in a sedated like state.