The tornado-tron!

You ponder which invention to use on your way back to your dorm, but when you spot her on the quad wearing a loose, flowy sun dress, you know instantly what you want to use. Sprinting into your room, you throw open the closet door and grab what looks like a large, homemade bazooka. You check a few gauges, make sure it's charged, and almost kick open your door to make your way back outside. Like a genitally challenged Terminator, you and your weapon march out into the sun, and across the quad in search of your prey. You draw a number of strange looks, but you don't care. You're on a mission.

You find her quickly, hanging out with her friends in the middle of the bustling quad. The perfect place for everyone to see her comeuppance. You rest the device on your shoulder and take aim. When you pull the trigger there is a loud thud, and a pretty solid recoil, but almost immediately afterword the red head's light flowy dress blows up, revealing a pair of lacy red boy shorts that scarcely cover her ample backside.

With a blush in her cheek she lets out a quiet squeak, and smooths down her skirt as a good number of the students around them share a laugh at her expense. You smile to yourself, knowing that she'll be thinking about their laughter for days. Is that enough, or do you need more revenge?