“WandaVision” episode 4 finally pulled back the curtain on the Marvel Cinematic Universe’s weirdest production yet. Disney+ viewers properly met the adult Monica Rambeau and discovered more about Carol Danvers’ “Avengers: Endgame” depression.

Monica (Teyonah Parris) was first introduced as a child in the 1990s-set “Captain Marvel,” released in 2019. Her mom, Maria Rambeau (Lashana Lynch), was Carol Danvers’ (Brie Larson) best friend.

However, Monica disappeared in “the blip” when Thanos destroyed half of all living creatures. She returned five years later exactly where she left off: in her mother’s hospital room. This time, however, her mom isn’t there.

Maria apparently had cancer. When Monica disintegrated, Maria had just come out of a successful surgery. However, a shocked doctor recognizes Monica and tells her Maria’s cancer returned just a couple years after she disappeared.

This further explains much of Carol Danvers’ downtrodden mood in “Avengers: Endgame.” There’s clearly a big difference between when she goes to space to fight Thanos at the beginning of the film vs. five years later, and it's more than just a haircut. It turns out she lost her best friend and her surrogate niece in that time jump.

Maria’s cancer also could be inspired by a storyline from the Marvel comics by Kelly Sue DeConnick. In the source material, Tracy Burke, Carol’s close friend on Earth, has no family left when she is diagnosed with cancer, and Captain Marvel takes care of her until she dies.

“WandaVision” also reveals that Maria had quite a life before her death. She founded S.W.O.R.D. (Sentient World Observation and Response Department ), and a plaque reveals her nickname as “Photon,” a big nod towards the comics and Monica’s possible future.

Photon is Monica’s superhero alias in the comics—one of many. She has also gone by Pulsar, Spectrum and even Captain Marvel. She has powers that include flying, manipulating forms of energy (gamma rays, X-rays, ultraviolet radiation, etc.) and phasing through solid matter.

It isn’t clear if Monica has powers yet. However, her brief appearance made it clear that she’s already had quite a career. She was grounded to “terrestrial missions,” much to her disappointment, indicating that she’s used to going on intergalactic missions.

Fans will have to wait and see which of these details ties into "Captain Marvel 2," which is currently due in theaters on Nov. 11, 2022. Meanwhile, "WandaVision" releases new episodes every Friday on Disney+. 

WandaVision Monica Rambeau Monica Rambeau (Teyonah Parris) appears in "WandaVision" episode 4. Photo: Marvel Studios/Disney+