Some of the most intense moments in Stranger Things 2 take place in the winding tunnels of the Upside Down that run underneath Hawkins. So, the actors involved in the tunnel scenes, like David Harbour, had to get the tunnel mud treatment. To come up with the perfect mud, Forsythe and her team spent some time in the makeup trailer experimenting. "We had a mud that we really liked, kind of like clays and that kind of stuff, but it didn’t quite have the texture that I wanted, and I wanted more textural layers to it. So, we were playing in the trailer, and we have an espresso machine in the trailer, so I took our concoction and I threw in the espresso grounds, and it was perfect. I was like 'This is amazing!'" said Forsythe.