Eleven and the water tank

In season one we saw an important flashback about Eleven.

Back in the laboratory Eleven was lowered in a sensory deprivation tank, enhancing her psychic abilities in order to spy a Russian agent. During one of these experiments she came across with a monster from another dimension. Once she made contact with the monster she panicked, creating a tear in reality between the two dimensions.

The gate with the Upside Down was created and everything started...

I hope you will like my creation