Rigby and Eileen's Children appeared at the end of the finale.
Both of Rigby and Eileen's daughters are taller than both their parents. They both appear to go bare foot like their parents. Their son is just about their height.
The oldest daughter is a raccoon and mole mix, as she has light tan colored skin, a small, round, light brown tail, and two toes on each of her feet, similar to her mole mother Eileen, however she has a pointed snout similar to her raccoon father Rigby. Despite this, most of her looks come from Eileen. During the montage, as a toddler, she has light brown hair tied back in a small ponytail, along with wearing red glasses just like her mom's, and she is wearing a white t-shirt with jean shorts. At the 25 year park reunion, her hair is now blonde and worn down past her shoulders, and she is still wearing red glasses. She is wearing a light blue sweater over a white shirt with long grey pants. Despite being the oldest, her younger sister appears to be a few inches taller than her.
The younger daughter is a raccoon like her father, she shows no traces of a mole. She has grey fur on her undersnout and the front of her body, and brown fur on the rest of her body, with darker brown lines on it. She has black circles around her eyes, and she has a long brown tail with 6 black stripes on it. During the montage, she is a baby. She is wearing only a diaper, and she has light brown hair that reaches her shoulders and it is worn down. At the 25 year park reunion, she has dark brown hair that is tied up in a bun, and she is wearing a pink tank-top that shows the bottom of her stomach and jean shorts. Despite being the youngest daughter, she is a few inches taller than her older sister.
The son is a brown mole like Eileen and is much shorter than both of his sisters. He appears to be the youngest of all the children.
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. Rigby and Eileen are seen married with two young daughters. Rigby is teaching the oldest daughter how to play a video game. Eileen walks in holding the youngest daughter, who is a baby at this time, and a plate of sandwiches for them.
The end of the montage shows the 25 year park reunion. Rigby and Eileen's daughters are grown up, according to the spinoff comic Regular Show 25 Years Later they have already graduated high school and are described as legal adults, making them at least 18-19. The older daughter holds up a piñata, which looks like Pops, and the younger daughter breaks it open, and candy pours out for some of Muscle Man and Starla's kids and High Five Ghost and Celia's son. They pose with their parents, their younger brother, and the other Park members and their families for a photo.
- Both daughters are tall, despite both their parents being short (or possibly having height problems since their other family members are tall).
- Rigby and Eileen's children were never given names.
- The younger daughter is a little bit taller than the older daughter, similar to how Don, despite being younger than Rigby, is taller than him, although Rigby is half Don's height, and the height difference between the daughters is only a few inches.
- Like Mordecai and Stef's Children and High Five Ghost and Celia's son, the oldest daughter is a mix of both her parents' species, in this case, a mole and a raccoon.
- However she looks most like Eileen.
- Both daughters have light brown hair when they are first seen during the montage, but at the reunion the oldest daughter is blonde, despite neitheir of her parents having this hair color, and the younger daughter has dark brown hair. There is a good chance they could have just dyed their hair, and/or this could be an animation error.
- Rigby introduces to them and teaches them how to play video games.