The cold intensifies as the spell slowly begins its change. You can see frost forming on strands of your hair that dangle down in front of your face. A potent stiffness begins to pervade your being as you struggle as hard as you can to escape from the spell circle. Yet despite how hard you try your legs feel as heavy as a pair of 2 ton lead weights. As the cold grows more intense, you find it hard to move at all; though what movements you do make chip away your clothing to reveal your naked form underneath.
Then comes an odd tingling sensation. It is not cold nor is it frostbite, but something else. You can feel parts of your body... shifting, almost as if they were morphing in some way as your body, regardless of your prior gender, was shifting to a feminine state. Your chest swells into a DD size, and your hips widen to form a sexy, curvy hourglass figure Your facial features become feminine as well as your hair grows out and down to your back. Your arms and hands become slender like a woman's, and whatever genitals you had before are now replaced with a tight, clean-shaven pussy.
As this transformation finishes, you find all voluntary movement up to this point has been robbed from you. You stand there; frozen and naked as your vision is blurred by the frost on your eyes; you wonder how things could get worse. And that's when you feel the tingling happen again as your body slowly starts to move on its own. Your shocked and pained facial expression slowly changes to one of a calm and inviting demeanor. Your back arches as your arms go behind your head; your legs posing as if you were showing off your body to some unknown lover. And once this pose is struck, your body fully freezes in it; trapping you there.
But oh, if this were only the end, for one final change was taking place. The cold at this point was so intense that your mind could barely register everything else; your vision nearly completely obscured by the frost. You felt as if your entire being was turning into ice as the color slowly drained from you; being replaced with hues of icy blue and white... and then a uniform icy blue as you slowly become semi-transparent.
And finally, when it is over, you stand there completely frozen solid; your body having been transmuted entirely into a statue of pure frost and ice; glittering and glistening in the dim light of the magic shop. You were trapped; still alive yet barely aware of anything other than intense cold. Completely helpless. You can only hope that the Witch might take pity on you and restore you...