Harmony.

Perhaps it was fate that made you look over the lunch hall before entering. Maybe it was nervousness at prospect of finally talking with Harmony again that made you go up to the second floor before lunch began and look down first. The lunch hall was just starting to fill with students, but the tables were already laden with food and the professors were already sitting at the head table. The looked positively giddy at the idea of lunch. Or perhaps it was something else that is causing their anticipation.

Out of the corner of your eye you see a distinctive platinum blonde head over to a seat in the corner. Oddly enough Harmony was alone again, her usual crowd of sycophants nowhere to be seen. Under her arm she was carrying a large model of a Soviet-designed self propelled anti-aircraft system. From your days spent playing video games back at home, you manage to identify it as a ZSU-23-4 "Shilka" with its distinctive turret and mounted radar. Strange, considering that Harmony never came off as a history buff or a fan of model making. She set the model down and began fiddling with various parts, her food completely ignored. Finally once she seemed satisfied, she tapped the model with her wand and it began to drive around, smoke coming out of its exhaust and turret scanning the horizon.

Soon you realized why she had that model, and it had nothing to do with her love of Cold War era combat vehicles. A huge group of animated valentines notes fell upon the eating students just as most of the tables begin to fill. Despite the fact that Harmony was the only one in the corner, a massive chunk of the notes began to move towards her. Various aircraft, flying creatures, lighter than air transports, and even rockets began to pelt the poor girl.

Or rather they would have had her model not started firing. Tiny bullets shred zeppelins, dragons, and rocket ships alike as the model stood its ground, determined to defend its creator. You watched in awe as her little model blasted holes into every single valentine's note that dared approach her. The students from your previous class were right about how many boys seem to be trying to proposition her for the dance. All of a sudden the little Phoenix you held in your hand seemed doomed as you watched the carnage in front of you.

This is going to take something stronger. You thought back to all the lessons you learned in your Charms and Transfiguration class, as well as some more advanced material that Hallgrave personally taught you during your tutoring sessions. You held your little Valentine's note close and began to chant. It was filled to the limit with words, having spent an excessive amount of time trying to think up of the perfect thing to say meant that the note was now just excessively long. It then began to shift in your hands and reorganize its shape. Out of its wings grew weapons hardpoints, out of its tail it grew a large twin jet engine, its head morphing into a cockpit, your Phoenix was now an F-18.

You threw the plane off the balcony and watched in horror as it began to plunge straight to the ground. You'd probably get expelled if somebody else read the stuff you wrote on that paper. However, at the last moment your fighter jet's engines roared to life and it began to pull up with increasing speed. It quickly circumnavigated the lunch hall before heading towards its target. It began with a shallow dive straight towards Harmony. Her head snaps up as she hears the scream of jet engines far louder than any other note. Her model snapped to attention and began unloading a stream of lead towards the attacking fighter, but the fighter was fast, faster than anything else in the room. The jet spun and tumbled to avoid the attacks at long range, when it got closer it entered a barrel roll launched its chaff countermeasures. Flares shot out from the back of the jet in order to confuse the radar system on the ZSU. The SPAAG no longer had target lock on the F-18 and began to fire wildly, sometimes destroying notes that were not even meant for Harmony.

The F-18 struck Harmony at speed and although it was made of paper, Harmony looked like she had been hit with a javelin, nearly falling off her seat. When she recovered she looked at the offending note, and before it could reveal its contents, incinerated the note with her wand.

Well I guess that's a fairly clear answer.