"S.", or the Mystery Girl, is a character that first appeared in "Last One Out of Beach City".
The Mystery Girl bears a close resemblance to Rose Quartz, as pointed out by Steven. She has voluminous medium-length hair that is dyed pink. She has defined lips with a grey ring pierced on her lower lip, and a slightly dark-peach complexion. She has a heavy build and is taller than Pearl, roughly around Garnet's height. She has green eyes and wears dark grey eye shadow and has thick eyelashes, and, aside from the aforementioned lower lip piercing, she has three grey earrings on each of her ears, with highest and middle piercing smaller than the lowest one.
In "Last One Out of Beach City", she wears a white (with a slight hue of pink) crop top with what looks like a simplified animal design, and with the sleeves rolled up. She also wears dark grey pants with the right leg having a rip near the knee, and black combat boots. She has a jacket tied around her waist; the jacket having various rectangular designs in varying shades of green similar to a camouflage design.
I asked her about her hair, and then she asked how I colored mine. I told her, "My appearance is just a conscious manifestation of light", and she said, "I know how that is", although, heh, I highly doubt it. Oh! And then I added, "By the way, I saved your planet, and your species, and you're welcome".
|—Pearl, "Last One Out of Beach City"|
Although not noticing Pearl at first at the Big Donut, the Mystery Girl catches up to Pearl, while the two are driving, and flashes her a smile. At Mike Krol's concert in Ocean Town, she checks Pearl out before she shakes her hand. The two of them discuss about how she dyed her hair and, briefly, the Rebellion. But before leaving, she gave Pearl her phone number, showing her attraction to the Gem.
|1. "Kindergarten Kid":||Absent||13. "Gem Heist":||Absent|
|2. "Know Your Fusion":||Absent||14. "The Zoo":||Absent|
|3. "Buddy's Book":||Absent||15. "That Will Be All":||Absent|
|4. "Mindful Education":||Absent||16. "The New Crystal Gems":||Absent|
|5. "Future Boy Zoltron":||Absent||17. "Storm in the Room":||Absent|
|6. "Last One Out of Beach City":||Debut||18. "Rocknaldo":||TBA|
|7. "Onion Gang":||Absent||19. "Tiger Philanthropist":||TBA|
|8/9. "Gem Harvest":||Absent|
|10. "Three Gems and a Baby":||Absent|
|11. "Steven's Dream":||Absent|
|12. "Adventures in Light Distortion":||Absent|
- According to Lauren Zuke, Mystery Girl's piercings were inspired by her World of Warcraft character.
- Lauren Zuke says they were "calling her 'Sheena' in [their] head" as a reference to the song "Sheena Is a Punk Rocker" by the Ramones. Her actual name is unconfirmed.
- According to the same blog, Mystery Girl is a smoker (though this will never be confirmed onscreen, since Cartoon Network doesn't allow smoking to be shown).
- S.'s phone number is 301-555-0189. The area code (301) corresponds to western Maryland, while numbers of the form 555-01XX are reserved for fictional use.
- Along with Onion and Rainbow Quartz, S. is one of the few characters with an important role that has not said a word.