We first see the “damn graveyard,” as Hop calls it, in fifth episode “Dig Dug,” although it’s not obvious that’s what we’re observing. The officer goes down into the tunnels after realizing the blight eating away at Hawkins’ farms is coming from deep below the surface. He does not expect to find miles of interdimensional tunnels hiding underneath his town, but, here we are. The sheriff is sprayed in the face by one of the valves containing the creepy white debris we’ve all long associated with the Upside Down, yet, so much enters Hop’s system he passes out. When he wakes up, he’s coughing up black goo. Eventually, he tries to get out of the tunnel, and breaks off a bone hiding in the space to create a makeshift torch. Despite his best efforts, Hop is soon enough trapped by the living vines surrounding the area. The tunnel is already so creepy, it’s not immediately obvious how bizarre it is that a human corpse is just sitting there among the crawling vines; this looks like the kind of place you would expect to find a dead body.