Stef is a one-time character who made her debut at the end of Season Eight during the series finale episode "A Regular Epic Final Battle". She is Mordecai’s wife and the mother of their children (two sons and one daughter).
Stef is a anthropormorphic bat woman. She has light mauve skin, long pointy ears, a black nose, visible fangs that stick out of her mouth, and reddish-brown hair. When Stef meets Mordecai, her hair is long and is styled so that it partially covers the left side of her face, and she is wearing a black choker with spikes on it, and a dark mauve top over some sort of black bra.
At the 25-year park reunion, her hair is short, and she is wearing a long-sleeved dark mauve top with white jeans, red flip flops, a key necklace, and a big sunhat. She also has wrinkles under her eyes.
Not much is known about her except that she's an artist. She loves Mordecai enough to marry him and have kids with him, a relationship that was likely influenced by their shared talent and love for art. During the park reunion, she's seen chatting with Eileen, showing that she's friendly and sociable.
Several years after the Park returned to Earth, Mordecai, who became a successful artist, is signing autographs at Mordecai and Stef met while they were both showing off their respective artwork at an art gallery. While they were signing autographs, they bumped into each other and gazed into each other's eyes. They eventually got married and had 3 children: 2 sons and 1 daughter.
She attended the 25 Year Park Reunion with Mordecai and her children. She was seen socializing with Eileen while her husband reconnects with Rigby and her teenage children occupy themselves on their smartphones. After everyone in the park came together for a group picture, she continued to talk with Eileen into the evening.
- During an AMA on Reddit with Matt Price and Calvin Wong, Matt confirms that they never really came up with a name for her. Matt gave her the name "Stef" because "JG loves Goonies [sic] so I'm going to say her name is Stef".
- Her name came from Stephanie "Stef" Steinbrenner from "The Goonies".
- Matt Price, the head writer, explained why Mordecai ended up with Stef instead of Margaret or CJ:
- "We felt like the Margaret / CJ story was complete, and they were both on their own path already. We also felt like Mordecai had moved on in his life. He finally left the park to pursue art, and we thought it'd be cool if he met someone while doing that. But we love Margaret and C.J., and we're sure that they're happy without Mordecai! He was too wishy-washy with them!!"