Her skirt

Ginny saw her skirt flying to the left, along the floor, and dove for it. She managed to grab it with both hands but it was still trying to pull away from her, leaving her bent over on her knees, her backside up in the air, displaying that on the back of her light pink panties was a darker pink heart with "love" written across it.

Her blouse, meanwhile, had flown up to find a flaming torch in the wall, and burnt itself to ash.

Ginny heard Hermione shout another spell, and suddenly she felt her panties yanked down to her knees. Unable to let go of her skirt in case it too destroyed itself, she was helpless as she suddenly felt her bottom being slapped repeatedly, jiggling as an invisible hand administered a spanking.

"Ow! Stop! Ow!" she cried out.