One of the biggest roles Hopper will be taking on in season 3 is that of official adoptive father to Eleven. Being the father to a teen girl comes with its own set of challenges even when you don’t involve the Upside Down, Demodogs, and mysterious laboratories. “Their relationship is going to get far more complex, because, you know, things happen to girls and boys when they’re 13 and 14,” Harbour told Variety . “A lot of changes go on in the body and in your social life, and I don’t think he’s going to handle watching her become a woman in front of his eyes very well. That’s a horrifying thing for him – maybe even more so than fighting inter-dimensional monsters.” Most dads aren’t ready for their daughters to grow up . Hopper might have helped save Hawkins with Mike, but even that kind of bond will undoubtedly be strained when Mike and Eleven get into what producer Shawn Levy terms a " fully-fledged middle school relationship.