> Experiment.
First and foremost, you should probably figure out what you can do to defend yourself. You expect it'll be necessary sooner or later, given your current species.
This in mind, you look down at yourself again, thinking your body may provide a clue as to what your abilities could be. It is then that you finally realize something patently obvious.
You take it back: first and foremost, you need to figure out how to even move. Your legs have been replaced by a giant, seemingly immobile book, so the obvious method is out. That's... really kind of horrifying, come to think of it. Like something out of a nightmare... actually, you should probably check and make sure this isn't just a nightmare, just to be sure.
You make to raise your arm and pinch yourself, not bothering to go with anything more subtle, since you wouldn't really mind waking up from a dream like this anyways.
Your arm refuses to obey.
...um.
You try again to lift your right-front arm. It stretches and bends a little, but refuses to do more than that — the paper that it's stuck in doesn't even budge. It's as if the end of the limb has been super glued to the pages of the enormous tome, which have themselves been glued into an utterly fixed position. The same proves true for your other three arms, causing your horror to mount and crest in record time.
No. No, this- this isn't- you can't just be stuck like-!
Before you can truly descend into panic, you're struck by a sudden understanding. Calming slightly, you realize that you do know how to move. You're not sure how you know, but...
Tentatively, you urge the giant book currently substituting for your legs to move forward. It does so, tilting downwards slightly in the process, which leads you to the sudden realization that you are floating. You've been floating this entire time in fact, you just couldn't really tell because you have no valid points of reference in this plane of nothingness. Even now, it doesn't really look like you're going anywhere, but you can feel yourself making slow, floaty progress all the same.
Well, it's nice to know that at least you're not trapped in place like a giant monochromatic statue. However, that still doesn't change the fact that you've somehow managed to become a witch with zero usable limbs. Just what kind of horrible karma did you somehow invoke to end up like this?! How are you supposed to prevent yourself from being instantly decimated by the magical girls that will inevitably come busting down your "door" when you're basically a witch quadriplegic?! You don't-!
Mid-thought, your mind once again answers you with information that you weren't aware you possessed. You momentarily still, processing this, before looking down at your upper book and mentally writing "testing, testing, one two three" upon the open pages.
The words quickly pen themselves into existence before nigh-immediately peeling upwards off the paper, turning three-dimensional in the process. Gradually, they begin to swell in size, placing themselves in orbit around your upper body as they do so. With a thought, you latch on to one of the testing's and send the word flying forward at a downward angle. It crashes into the floor (so there is a floor) and shatters into hundreds of small, inky black shards with a sound not entirely unlike breaking glass, before its scattered remnants of quickly fade from existence.
Looks like you've found your primary method of defense. Though, something about that looked slightly... off, to you.
You bring the remaining words around in front of you to examine them, and instantly realize why — this isn't Japanese, it's those weird runic symbol things you've seen floating around in a couple of witches' labyrinths. For some reason, you can now read them effortlessly, despite having had no idea what to make of them before.
Is this... witch language...?
You put the thought aside for the moment, having too many other things to focus on right now to consider it a priority, and cast the remaining words into the floor as well so they won't distract you. Besides informing you how to make and fling giant word projectiles around, your mind helpfully supplied you with the knowledge of one other thing, which you would rather like to try out.
Looking out into the blank white void that surrounds you, you attempt to impose your will upon it, imagining a flourishing tree growing upwards from a specific spot in front of you. Instantly, it appears, sprouting up from the unseen ground until it's grown to almost three times your height. On a whim, you proceed to change the small fruits budding from its branches into overgrown precious gems, weave crystalline lines of silk throughout the foliage, and turn the entire trunk to dark stained glass. Then you let the whole thing dissolve, fading away into the nothingness from which it came.
Illusion control. Impossible to physically interact with, but virtually unlimited in scope. That's... extraordinarily cool, to be perfectly honest. The possibilities for an ability so free-form are nigh-endless, as long as you have enough imagination to pull them off.
...that being said, the fact that you even know how to do that, as well as that shatter-word attack, is more than a little unnerving. These clearly aren't things that the human you should know, which means they must be instincts coming from your witch form. "Witchstincts", so to speak. They're certainly convenient — who knows how long all this would have taken to figure out without them — but it's rather discomfiting to know that you have them at all.
[-] Continue. You've already started down this path, so you may as well keep going. What else can your witchstincts tell you?
[-] Exit. You don't know exactly where to, but the "white on white" décor, or rather lack thereof, is very quickly getting old.
[-] Summon. Witches have familiars, right? Can you call on them? Command them? Have them lead you out of here, perhaps?
[-] Free. Your arms, that is. Who cares if you can attack without them? You still want your appendages back, dang it. Surely there's something you can do…
[-] Have that delayed mental crisis about witches possibly retaining their minds now.
[-] Write in.