Erica is the somewhat typical annoying and little sister to Lucas and a source of irritation to him. She constantly calls him weird and annoying due to his nerdiness and for the same reason isn't fond of Lucas' friends, thus barely showing any respect to them. However, despite her abject disapproval of nerds, it is revealed in the third season that she is a math whiz and therefore a nerd herself. It's also implied she sneaks into his room and steals his stuff, such as Lucas' He-Man action figure. Additionally, while she does not doubt the existence of the Upside Down and the creatures that come from it after Dustin explains them to her, she initially refused to believe that Lucas was involved with either of them until he helped save her from the Russians. She is also incredibly self-centered, choosing to help Dustin, Steve and Robin infiltrate the Russian base beneath Starcourt Mall with the promise of free ice cream and protecting capitalism rather than out of patriotism.
On the morning of October 31, Erica watched as Mrs. Sinclair photographed Lucas in his Ghostbusters costume. She taunted him, calling him a “nerd”.
Erica was having breakfast with the rest of her family when Lucas asked their father for advice. Later, when Dustin Henderson was trying to contact his friends to warn them about Dart, Erica, who had sneaked into Lucas's room, was the only one to answer him. Dustin tried to explain to her the severity of the situation, however, Erica didn't listen and turned the radio off.
The next day, Erica was playing in her room when Lucas came to retrieve his toy she had taken from him. It was then that she finally revealed to Lucas that Dustin had been trying to contact him.
On the night of the Snow Ball, Erica again made fun of Lucas after she witnessed him talking in front of his mirror, practicing how to ask Max Mayfield to dance.
- Erica is the second youngest sister of a member of the Party; after Mike's baby sister Holly.
- Erica is a fan of My Little Pony.
- Erica is the second main character of Stranger Things to be dark-skinned; the first being her brother.