5 theories about the new monster in Stranger Things 3

A Hawkins rat that’s been infected by the Upside Down by accident or on purpose

In the trailer, we see this monster growing and evolving as Dart did in the second season. As Jonathan watches on from just down the hallway, this monster obviously starts small and then gets bigger and bigger. Rats are going to play an important part in Stranger Things 3, and so it seems like it’s possible that a rat could become infected with some other-worldly virus and turn into this monster

There’s so much about the Upside Down that we don’t know, and it seems like there are multiple ways a rat could be infected.

We have to imagine the tunnels under Hawkins are still full of matter from the Upside Down. Maybe they were closed when Eleven closed the tunnel, but there was so much damage done and the tunnels were so intricate that it feels possible that the rats could have invaded, thrived, and ended up like this monster.

We also know there are some bad dudes in Hawkins. The Hawkins National Lab was under some horrible leadership in the first season. Those secrets about the Upside Down, Eleven and the other weird happenings in Hawkins would intrigue a lot of people.

I wonder if the Upside Down could be weaponized. Rats and mice are often used as test subjects. Perhaps, someone was testing a product derived from the Upside Down, and the monster is what you get when you inject said product into rats. It’d be an interesting direction to take the new season.