The Upside Down and its Creatures

The Upside Down is basically an alternate dimension of our world. While it may have the same exact scenery, the air is full of toxic spores and there are many dangerous creatures who are controlled by the shadow monster/mind flayer.

While all of these creatures are controlled by the mind flayer, they all have different purposes
and stages of life.

1. The demogorgon is the first creature we see from the upside down that appeared in season 1.
2. The slug is the youngest form of a demogorgon. It grows small legs and grow into a demodog.
3. The demodog is the next stage of life for a demogorgon. They are seen together in a pack in season 2.
4. The mind flayer/shadow monster comes in many forms. From a gross pile of flesh, to taking over a human host, to being a huge shadow, the mind flyer always finds a way to exist in a terrifying way.