|This article is about the artificial intelligence. You may be looking for the facility she manages.|
Welcome, Pink Diamond.
|—Shell and Steven, "Volleyball"|
Shell is an artificial intelligence integrated into The Reef, and the primary antagonist of the episode "Volleyball". She attempts to heal Pink Pearl's crack by rejuvenating her and Pearl. After they fuse into Mega Pearl to escape, she then attempts to kill the newly formed fusion and Steven. They escape Shell and destroy her security system.
Coded to act as a guide for possessors of Pearls, Shell is, at first, soft spoken and helpful to Steven, Pearl, and Pink Pearl, as they walk through the facility of the Reef in search for a means to heal Pink Pearl's cracked eye. Once Steven loses his temper, however, Shell turns against the two Pearls and acts in harsh ways to "fix" them, locking them in an oyster and attempting to rejuvenate them, even as Steven pleads for her to stop. This showcases how Homeworld and those who programmed Shell used to be, as she retains the characteristics of an authoritative government. The A.I. is not programmed to recognize fusions; upon the formation of Mega Pearl, Shell becomes even more aggressive, believing her to be an unknown entity, and activates her defense system to intercept and capture her. Shell is ultimately turned off by Steven.
Shell is programmed to be both a guide and a guardian to The Reef, being in full control of it. She can light up paths indicating the way toward a room, offer information to visitors, scan Gems with sensors, and rejuvenize rebellious Pearls — all to meet the owner's wishes.
In her position as a keeper, she can activate a defense system to attack unauthorized personnel. When it is initiated, the facility becomes weaponized: the doors are locked, and Shell utilizes laser beams, stretching ropes, and panels to prevent any intruder from leaving. Despite this, her activation panel can still be accessed and used to shut her off.
Shell is first heard when Steven presses a hand sensor at The Reef. This notifies Shell, who takes him, Pearl, and Pink Pearl on a tour through the facility. Eventually, she attempts to fix the crack on Pink Pearl's face, but fails. She explains that there is nothing wrong with the gemstone, so the crack is lingering due to psychological reasons. Later, when Pearl and Pink Pearl start arguing, Shell apologizes to Steven for their bad behavior, calling them defective and attempting to rejuvenate them.
When the two Pearls fuse into Mega Pearl, Shell does not recognize the new entity, and therefore attempts to neutralize her. Mega Pearl dodges and destroys most of Shell's security system. Shell, using panels, blocks off Mega Pearl from shutting down the defense system, but she simply throws Steven to do it in her steed, who succeeds.
|1. "Little Homeschool":||Absent||11. "In Dreams":||Absent|
|2. "Guidance":||Absent||12. "Bismuth Casual":||Absent|
|3. "Rose Buds":||Absent||13. "Together Forever":||Absent|
|4. "Volleyball":||Debut||14. "Growing Pains":||Absent|
|5. "Bluebird":||Absent||15. "Mr. Universe":||Absent|
|6. "A Very Special Episode":||Absent||16. "Fragments":||Absent|
|7. "Snow Day":||Absent||17. "Homeworld Bound":||Absent|
|8. "Why So Blue?":||Absent||18. "Everything's Fine":||Absent|
|9. "Little Graduation":||Absent||19. "I Am My Monster":||Absent|
|10. "Prickly Pair":||Absent||20. "The Future":||Absent|
- As an A.I., Shell can be categorized as both an object and a character.
- Shell shares the same tone as Pearl when the latter asks Greg to identify himself in Steven Universe: The Movie.
- Shell was never updated in the transitions to Era 2 or Era 3, showcased by the Era 1 symbol in her activation room and how she treats Pearls as objects bent to the wills of their owners.
- As Gems can be classified as sentient forms of A.I., it is possible that Shell is a modified Gem, presumably a Pearl.