Honestly Ruby wasn't sure which one to do. One of the shields definitely. One of the ones that had substance to it since conjurations were totally her thing. Revertoscutum could be fun.... so could Impiriano, which was SUPER pretty, and she was well enough able to project either of those shields over the astronomy professor. Actually they were both pretty shields... Ruby decided that one would be far more fun to demonstrate than the other though.

When it was her turn she sashayed forward.

"I'm going to do revertoscutum, Re-ver-toe-skew-tum, its a shield which reverts stuff when it goes through it. Wand movement is super easy, you just point. Like this."

She pointed her wand at the professor. "Revertoscutum!" The resulting shield that shimmered into place around him looked like water, a pretty pale greenish blue, but you could still see through it of course.

"Its one that you usually do around yourself, and it moves with whoever it is anchored to, but you can move it around someone else, its just kind of tough and takes practice and concentration." And honestly, she would MUCH rather protect her own self. Just saying. "But obvy we have to see how it works soooo..." Ruby cast silently and a stream of little yellow birds appeared from her wand and flew directly at the professor and his shield, divebombing.

.... and birds after all came from eggs, sooooo once they flew through the shield, hopefully Flamsteed would be quick about dodging the tiny eggs that they should revert to, or he'd have some on his face. And suit. She watched avidly to see what he would do to avoid it.