Arrivederci.

A Stand is a supernatural power in Jojo's Bizarre Adventure, introduced in Part 3: Stardust Crusaders and featuring heavily in all subsequent parts. Canonically, Stands are viewable only to other Stand users — this may change in different game settings! They are described variously as a person's fighting spirit or a representation of their psyche. Whatever they are, they protect their users (with a few notable exceptions) as well as represent them in a way vaguely analogous to (but less understood than) the dæmons of His Dark Materials, or the Personas of the eponymous franchise.

When Stands are hurt, so too are their users, and vice versa; when a Stand dies, so does its user, and vice versa. Stand users have been known to see ghosts, presumably due to their connection with the spirit world through their Stands. There are several types of Stand.

Spice Girl, as stated above, is the manifestation of Trish Una's soul. As such, she echoes the core traits of her user in both subtle and significant ways. These include physical traits like a shared physique, and other more integral and unseen parts – particularly Trish's desire for safety, her resilience, and her initially obfuscated gentle nature. In accordance with this, Spice Girl's primary ability is to soften any objects she strikes (or in Trish's case, any object she touches herself). Softening confers a rubbery, elastic quality to any object, including metal, glass, and rock. Under the influence of this ability, these objects are essentially indestructible, snapping back to shape when smashed and resistant to puncture by sharp weapons, making them much more durable than they were previously. Any force applied to the same objects will also either be reflected back punishingly or stored as kinetic energy to create surprise attacks when the effect is lifted, restoring the object's momentum. This is shown in a battle where Trish softens bullets so that they flatten harmlessly and unnoticed against her enemy's hand before releasing them later.

In a manner of speaking, Spice Girl's ability is evocative of the principles of topology, a mathematical construct that describes certain objects and spaces that preserve their properties regardless of any deformations applied to it, such as twisting, stretching, or crumpling. In fact, it's sometimes referred to as "rubber-sheet geometry" because the objects can "be stretched and contracted like rubber, but cannot be broken". Of course, there are exceptions in topology, just as there are exceptions to Spice Girl's power; specifically, that her power only works on inanimate objects and not living creatures.

Regardless, her power allows Trish to manipulate her surroundings, turning practically any environment into a swath of opportunities for shields or weapons in equal measure, including floors, walls and ceilings. Additionally, neither Trish nor Spice Girl have to maintain contact for their power to persist, and they can remove its effects at will. This allows for passive, practical applications like rendering fragile objects unbreakable to aid in their transportation. Nifty!

Beyond this, Spice Girl has another characteristic unique among Stands as a whole, one that allows her to serve a further purpose as a source of guidance and strength for Trish. In short: while Stands can have unique mannerisms, they often do not speak and usually abide entirely by their user's commands, acting as an extension of their user rather than as a separate entity. Spice Girl, however, is a Sentient Stand, with a mind fully separate from Trish's. This actually creates an instance of misunderstanding between them when Spice Girl expresses confusion at Trish's actions during their fight against Notorious B.I.G., querying her on why they ran away from the cockpit of the plane, where she had instructed Trish to go. Calmly, she explains that she intended for Trish to "move slowly" towards it, instead of running to hide in the closet at the back of the plane. Of course, Spice Girl was unbothered by the horrific Stand laying between them and their goal, while Trish was too terrified to fathom anything but putting as much space between her and the automatic Stand as possible. It's a humorous spot in a desperate situation, and ultimately Spice Girl is able to patiently guide her flustered user and show her the indestructible monster could be beaten. Indeed, her goal seems to be to inspire Trish to take the reins and not to direct her forever, nor quarrel with her, keeping a cool head under pressure and instructing her user until she's able to take on a more passive role under Trish's command.

Interestingly, she also asserts she's been present since Trish was a little girl, but has only been able to manifest very recently after Trish herself had become newly able to see Stands.

Spice Girl is varying shades of pink with a dash of red and yellow, all applied to a feminine physique that closely resembles Trish's own build. Apparently her design is...based off the noble cat, though you might have to squint to see it. The most cat-like feature she has is the shape of her eyes and face, and otherwise she calls to mind the image of a warrior, with pauldrons and a metal skirt and a head that is shaped obliquely like a Corinthian helmet. Like Trish, she tends to curl up around her knees into a ball, which may or may not be another nod to cats, or a habit meant to reflect the defensive way Trish is often seen curling up herself during early Vento Aureo.

Her face and body are also adorned with several mathematical symbols, the very same that can be found on Trish's signature skirt.

+ - x ÷

Whether these could be a nod towards topology in a tilt-your-head sort of way, or an implied love of math in Trish herself, their nature is left up entirely to the audience's interpretation. Araki is on record saying he added them to "look cool", though. 

FELFRI | RYSLIG