Mordecai and Stef's Children appeared at the end of the finale, at the 25 year park reunion.
All 3 children are blue jay and bat mixes. They all look like Mordecai, especially the two sons, but they have long bat ears and brown hair.
The two sons look most similar to Mordecai, as they have the same feathers and features as their dad, but they do not have black stripes on their fingers. The oldest son has dark brown hair and grey and pink bat ears. He is wearing a white t-shirt with the sleeves ripped and tan shorts. The younger son has light brown hair and blue and pink bat ears and wears a red t-shirt with pale purple jean shorts.
The daughter also looks like Mordecai and has most of his features, but she is light purple, similar to her mom, she has dark brown markings on the sides of her head instead of black, and she does not have stripes on her arms, fingers, or tail feathers. She has short light brown hair, light purple and pink bat ears, and she is wearing a teal tank top and a black skirt.
After the final battle between Pops and Anti-Pops, which resulted in Pops sacrificing himself to destroy his evil twin and save the Universe, the Park returns to Earth after being in space for 3 years. A time montage is shown, which takes place over a course of 25 years, showing the characters' futures. Mordecai becomes a successful artist, and he eventually gets his own art gallery. He is signing autographs, and he bumps into another artist who is also signing autographs. The other artist is Stef, a bat-like girl, and the two turn around and stare into each other's eyes.
At the 25 year park reunion, Mordecai and Stef are now married and they have 3 children. They all appear to be around their teen years, and they are all occupying themselves on their smartphones, looking annoyed. They pose with their parents, and the other Park members and their families, for a photo, with the daughter and the youngest son still appearing annoyed.
- Like Rigby and Eileen's oldest daughter and Hi Five Ghost and Celia's son, Mordecai and Stef’s children are all mixes of both their parents species, in this case, a blue jay and a bat.
- Mordecai and Stef’s children were never given names.
- In the 25 year park reunion photo, the oldest son has eyelashes.
- The youngest son has a skateboard.
- Along with Hi Five Ghost and Celia's son, they did not appear until the reunion.