"Marco Jr." is the second segment of the fifty-second episode of Star vs. the Forces of Evil. It premiered on March 17, 2018 alongside "Is Another Mystery", and is the second segment of the seventeenth episode in the third season.
Marco returns to Echo Creek to discover that his mom is pregnant.
Marco and Star arrive at the Diaz House for a visit. They have been invited for a baby shower, but are unaware for who. They are greeted by Angie who reveals that she is pregnant, shocking, but also exciting Marco. Because it is supposedly a boy, she and Rafael have opted to name the baby Marco Jr. due to the baby having a mole as revealed on the ultrasound. They celebrate where Star feels the baby kick, but when Marco tries is disappointed to not feel anything. They realize that the invitation that they got said to bring a gift, something Marco neglected because he did not bother to read it properly. Desperate, he and Star decide to leave the party and head to Quest Buy to get something for Marco Jr.
Star attempts to help Marco find the best baby gift, but he is dissatisfied with all of her suggestions until they head to the basement of the store and meet Cobalt Ferrero, a painter. His paintings turn out to be magnificently realistic and Marco decides her wants one so that it can feel like he is always home. Due to the process, Marco pays $650 to get one made quickly which results in him having to take an exam like questionnaire to get all the detail. Being careless, Marco fills it in with random answers and the painting is finished. He and Star get back home, but when they present the painting, it is hideous, disappointing Marco.
As Star and the Diazes sit for dinner, Marco's face begins to alter to that of the painting, limiting his movements and face. Star tries destroying the painting, but it does nothing. They head back to Cobalt who reveals that the owner shifts to the paintings perception and offers for him to take another exam. Angie and Rafael decide to answer the exam for him, but when it becomes apparent that they know nothing about their son, Star takes over and answers everything accurately. Marco returns to normal and he agrees that he needs to visit his parents more often.
- Eden Sher as Star Butterfly
- Adam McArthur as Marco Diaz
- Artt Butler as Rafael Diaz
- Nia Vardalos as Angie Diaz
- David Krumholtz as Cobalt Ferrero
- The episode was to premiere on January 22, 2018, but it was delayed.
- "Marco Jr." is also the name of the one of the laser puppies, as revealed in the second "#MarcoLIVE" animated live chat with Marco Diaz.
- Angie is stated to have gotten pregnant some time after Marco left for Mewni in "Sophomore Slump".
- When Star is filling out Marco's personality quiz, she marks down 26-35 as his age, most likely referencing the time he spent in Hekapoo's dimension in "Running with Scissors" and "Night Life".
- Gustav a.k.a. Charlie Booth, returns since "The Other Exchange Student". The Diazes are still unaware of his true identity. He has no speaking lines in the episode.
- Marco's portrait being a reflection of himself and him becoming the painting is a reference of Oscar Wilde's The Picture of Dorian Gray.
- Angie reveals that she was in labor with Marco for 37 hours.
- "Disney Television Animation News post". Twitter. Retrieved on December 31, 2017.