First introduced in WandaVision episode 2, Scarlet Witch and Vision’s neighbor (and unwitting magical assistant) Geraldine was a bit of a surprise appearance. Let’s get right down to business, because there’s a lot going on with the mysterious Geraldine.

Who is Geraldine, Really?

We’ve known since the show was in the casting stages that Teyonah Parris was playing Monica Rambeau. So when Parris showed up with a different name on the street, it was a big clue that something was up. And indeed it was: WandaVision episode 3 saw “Geraldine” opening some real cracks in the reality that’s been constructed around Wanda, before she was unceremoniously hurled out of Westview at episode’s end.

Who is Monica Rambeau?

Monica Rambeau does have some comics history with Wanda. Currently known as Spectrum, Rambeau was introduced to the Avengers as Captain Marvel. She’s the daughter of Frank and Maria Rambeau, and if that last name sounds familiar, it’s because it’s another tie to her first MCU appearance – as the daughter of Carol Danvers’ best friend in Captain Marvel. MCU Monica was still a kid when we left her, but that’s because Captain Marvel took place approximately 25 years before WandaVision.

So Why is Monica Rambeau on WandaVision?

Monica’s powers are the most likely nexus to the show. SWORD, the mysterious agency that we’ve seen monitoring Wanda’s neighborhood, rebranded when it made the jump from comics to television, from an agency monitoring for extraterrestrial threats to an agency monitoring “sentient weapons.” One theory about what SWORD is doing has them monitoring beings whose powers are awakened by a zap from an Infinity Stone. Wanda’s powers were first awakened by the Mind Stone in Avengers: Age of Ultron, the same way Carol’s powers were granted by her blast from the Space Stone. Like the Carol of the movies, Monica got her powers from a mysterious energy blast, and she has a nexus to Carol in the MCU. It’s entirely possible Monica has powers she got from her association with Carol.  Monica can transform herself into electromagnetic energy. She can absorb energy, channel it into energy blasts, convert her body into any form of electromagnetic energy for travelling purposes, blind people with light flashes, fly through space unaided, read energy trails, and so on. She is by definition an sentient weapon, and chances are good she’s a SWORD agent on purpose because of those powers. Then again, she could just be working for SWORD and not have any powers. But that’s no fun. There are some more theories you can check out here.