Stranger Things Season 2: 9 Crazy Fan Theories (That Might Actually Be True)
8. Hopper's Daughter Was An Experiment
Detective Jim Hopper was one of the many bright spots of Season 1, played with a great world-weariness by soon-to-be-Hellboy David Harbour, but there was also a real tragedy to the character too. It was revealed that his daughter, Sara, had died from cancer, which propelled him towards alcoholism and was a major driving force behind his search for Will and relationship with Eleven.
Sara's illness started when she was in the park and suddenly started to hyperventilate. With little explanation behind that, could it be that she was - like Eleven - a psychic, and perhaps even glimpsed the Upside Down? It is a little bit of a stretch, but Harbour, when asked about his daughter in a Reddit AMA, said:
"Yes, but it's a secret we may explore in s2, so don't wanna say right now."
Maybe that's just teasing, but it certainly hints at there being more to his daughter's death than we've been told. It'd tie-up that mystery and explain why Hopper becomes so invested in Eleven, without being too neat - like the theory that it's Eleven herself who is Hopper's daughter.