One of the surprise characters from season 2 of Stranger Things was that of Lucas' younger sister Erica, played by Priah Ferguson. She was delightful as the antagonizing younger sibling, which definitely brought back memories for many people. In a recent interview with Yahoo!, co-creator Matt Duffer spoke about how Ferguson was cast, saying:
"I love Erica. [Ferguson] was just a local hire we made in Atlanta. Erica wasn’t even supposed to be in [Season 2] as much as she was. We fell in love with this girl."
In the same interview, Ross Duffer talked the character and season 3, saying:
"There will definitely be more Erica in Season 3. That is the fun thing about the show — you discover stuff as you’re filming. We were able to integrate more of her in, but not as much you want because the story [was] already going. ‘We got to use more Erica’ — that was one of the first things we said in the writers’ room."
Ferguson was interviewed for Vulture and has hopes of going on a dangerous adventure:
"It would be cool if I were back, and maybe also get into fighting the demogorgons, because my response from when I was looking through Lucas’ room for He-Man, I think is a little clue that Erica may be sneaky and may find something from the demogorgon."