Thunder

A low rumble split the air, and Sabrina looked up just in time for a drop of rain to land on her face, followed by another.

"Don't worry, class." her teacher called, "It's just a little rain!"

For the rest of the students it was nothing to worry about, but unlike Sabrina they weren't naked under a paper dress. Sabrina looked down at the increasing amount of water falling on her outfit, and let out a squeal of surprise, annoyance and impending embarrassment. This noise drew the attention of the class, just at the worst moment.

To everyone under the effect of the glamour spell Sabrina was wearing a normal dress, so it was especially surprising to see it fall apart under the effect of the rain, breaking into soggy pieced and dropping from her body to land in a mess on the ground. As her pert breasts, nipples standing hard in the chill air, were revealed Sabrina spun around, away from the students. She regretted this as her previously quite dry back now began to soak up the pouring rain, and the paper dress parted right over her firm round buttocks, the skirt of her outfit peeling away and landing at her feet.

Sabrina turned on the spot, trying to find a way to keep her dress on, but she failed miserably as the rain turned the paper into a heavy mush which dropped away.

"Oh, no!" Sabrina exclaimed, her naked young body revealed again. She grabbed at herself with her hands, trying to cover her crotch, her hard pink nipples, rain pouring down the curves of her skin, plastering her blonde hair to her head, chilling her body.

The students erupted in laughter at the sight of the girl now standing before them completely nude, squirming as she tried to hide herself from their sight.

"Sa... Sabrina!" her teacher cried, "What on earth?!"

"I... I can explain!" Sabrina gasped, before thinking for a second and then adding, "Actually, no I can't."

She might have had a better chance if she had tried to go home then, but whether the effect of the curse did something to her decision-making or she just wanted to get away from the people who were looking at her right now, Sabrina dashed back inside the school.