Well Hermione, of course.

After Charms class Ron headed to the library, a place he knew Hermione would be with the free period between charms and potions. He was feeling anxiou to try out the device and worried that it would not work.

Finding Hermione sitting in her normal spot with piles of books around her. Ron was glad the library was mostly empty, taking out the ray gun he set the dial to level 3.

The device started humming in his hands, luckily it was a quiet hum. Aiming the device at Hermione he pulled the trigger.

<Zap>

A pink beam shot out and engulfed Hermione in a pink light.