In Case You're Looking For Some Nightmares, Here Are All the Monsters From Stranger Things

This is the OG monster of Stranger Things, stalking the town of Hawkins throughout season one. It vaguely resembles some sort of monstrous amphibian species and originates from the Upside Down before emerging through the gate to kidnap victims (such as Will and Barb). Season one's Demogorgon is an "adult," walking upright and even possessing some supernatural abilities such as low-grade telepathic or telekinetic abilities.

Underneath Hawkins, connected to the Upside Down, grow sentient, dangerous vines. They resemble tentacles more than your standard-issue garden vines and are super-strong, capable of tying up a grown man. Fortunately, they're susceptible to sheer force and fire.

Season two sees the return of the demogorgon species, but this time, they're not fully grown. Dustin finds one, whom he nicknames "Dart," and sees it grow from a lizard-like pet to a midsize monster. The demo-dogs aren't as strong or powerful as their adult counterparts, but they're still formidable, especially when being commanded by the Mind Flayer. Dart, for one, was able to ignore the Mind Flayer temporarily and choose to not attack Dustin in the tunnels, recognising him as a friend.

The big bad of season two is a tentacled monstrosity that not only attacks physically, but can possess and control his victims. A huge part of season two is devoted to his growing control over Will and the gang's attempts to free Will from his control. The Mind Flayer is, essentially, the big "boss" of the monsters from the Upside Down, controlling them in apparent hopes of wiping out all of humanity.