
This character is Aurora, a raccoon who lives in Elseways, on the University grounds. She's physically unremarkable - a raccoon of normal size and shape - apart from the copper-colored lightning-bolt collar she wears, you might think she's just another animal. She's a bit more than that, though; Aurora has the inherent ability to generate and control electricity. Like Skye Bergstrom, her physical changes are too subtle to see most of the time, but her fur has an odd texture to it; it's stiffer and almost feather-like, which means she poofs quite dramatically whenever she's surprised. Likewise, her ability is like Skye's ability to create balls of light; it's based on how magic works in Elseways, which is a system I've nicknamed "ratiomancy".
Magic is an inherent part of a person - they either have it or don't, and (short of cheating) there's no way to change that. It's not all fun and games, though. Sure, you get some kind of supernatural power that effectively turns you into a superhero (and, in fact, many magicians keep their ability a tightly-held secret), but there's a cost. To fuel your power, your body requires you to eat some kind of substance. Exactly what this is varies wildly from person to person - it could be as common as wood or ice, or as rare as a specific herb or gemstone. This fact is balanced by the fact that things which are more rare or specific will have a greater restorative effect. However, it's not so straightforward, and this is where the "ratio" part comes in.
A magician's energy level can be expressed as a fraction like 21/25, or a percentage - ideally, it should stay as close to 100% as possible. There's nothing keeping it there, though; the "numerator" drops slowly over time. It even drops while the magician sleeps (although more slowly than while awake), which means a good night's rest may feel nice but won't really help that gnawing hunger. Every time the magician's power is used, the numerator drops even more quickly. Below about 50%, the hunger starts to become overwhelming, and at 0%, they're completely drained and will be unable to think about anything else - of course, no matter how much else they eat, they'll stay hungry as long as their specific need goes unfulfilled. It's a different kind of hunger, but it has much the same effects. Overeating, however, causes much different things to happen.
There's nothing keeping the fraction from going above 100% - in fact, some people do this on purpose for the high it gives them. Eating their specific food increases the numerator by the same amount no matter what, even if they're already "full". Up to around 200%, the effect is a kind of euphoric madness and a loss of control of their own power. This is self-correcting in most cases, since using it will drop the percentage back down, but the problem is that they have no actual control over how it behaves. Aurora in "overdrive" mode would just shoot lightning bolts randomly (and from this picture, it looks like she's up around 110% herself). A healer might turn carcinogenic, while a shapeshifter might turn monstrous. It's possible to go over 200% - there's no theoretical maximum - but at some point, the magician's body will be unable to contain the vast amounts of built-up energy, and without a release, this can be fatal.
The denominator of the fraction never drops; it only builds slowly but steadily upwards over time as the magician uses their ability over and over again. This has two main effects - one is that they can hold more energy, so they progressively need more and more of their key substance to keep going. The other, though, is that they can use their power more without worrying about running out, and they're less likely to go into overdrive mode. Of course, if they do, it'll just take that much longer to get back to normal; this can lead to fairly dangerous situations.
Aurora, for her part, is actually more skilled than she appears; she's an unofficial magic instructor at the University (there are no public-knowledge magic departments there, mostly because the University respects a magician's right not to out him/herself, and so the meetings are generally secret and unofficial). She's sensitive to the signs that magicians exhibit, and can directly estimate someone's energy ratio to within the nearest 10%. Aurora's key food (and I could use an actual term for these "key foods") is garlic, so she makes sure to keep a large stash of it around just in case.