"Aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa!"

The Doppler Effect is a phenomenon that occurs when a source of sound is in motion.

"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaHHHHHHHHHHHHHHHHHHHHHHHHHH!"

It is described as an apparent change in the pitch of a noise in relation to an observer.

"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH!"

When the source of a sound increases in velocity, so too does the variation in the Doppler Effect.

"AaahaaaaaAAAAAaaaaaaAAAAAAaaaaaaaaAAAAAAAAAAAAAAaaaaaaaHHHHhhhhHHH!"

Out along the edges of Hogsmeade was a little-known shop by the name of 'Honest Malcolm's Discount Mountain,' a place where one could find all sorts of curios for allegedly 'honest' prices. Operative word being WAS, because now all that remained of the store was a smouldering ruin and its former proprietor tearing across the cobblestones in erratic dysfunction whilst engulfed in a curiously green blaze. His screams grew louder and louder as he raced down the way, spreading his flames across the stones he trod upon to the anguish of many alarmed onlookers who now needed to dodge out of his way. Among those onlookers were a pair of Hogwarts 5th years, both of whom parted alike the biblical red sea when Moses-Malcolm made his way through.

With him running past the two students turned their gazes back the direction he came, just in time to see a sphere brimming with crimson force rocket out of a window and explode violently against a splintering, smouldering wall. It cracked to pieces in spectacular fashion, spraying wood chips and small gouts of flames onto the closest gawkers and causing the crowd to disperse like frightened mice at the sight. Left behind were the two students, a small raven-haired girl called Evalyn and the athletic, well-built Ava Boyd. Initially on the hunt for a certain escapee from the school's fitness club (among other offenses), the two hadn't bargained to run into explosions and especially not for what came next.

Out of the embers with wand in hand was a pale, dark-haired girl wearing the trademark green-trimmed robes of Slytherin, who lazily walked through the wreckage until she reached the streets ahead. While Evalyn stared taken aback by it all, Ava had no such hesitation and ran forward to meet the apparent arsonist. "Wot in Helga's teats are you doing!?" The Hufflepuff shouted whilst putting her hands on the girl's shoulders to give her a sharp shake. "Amelia! Amelia say something!" She added after a few seconds of silence where Amelia did naught but scan the area with a stare not dissimilar from that of a hunter stalking their prey's.

"Ameli-!" Before Ava could finish that word Amelia lifted a finger to her lips and brushed her aside, walking a little ways past her to look at the slowly receding trail of flames left on the cobblestones. "I'll never forgive him." She said in a low, quiet voice before proceeding along the path, her eyes never straying from the fire even as she passed quite close by the bewildered Evalyn and away from the store. Once she was a fair distance away she lifted a hand and performed a lazy snap of the fingers, and with a snap; crackle; and pop the store's flames burst into a puff of smoke and vanished. Evalyn looked from Amelia back to Ava, lost for words and mind racing with possible scenarios for what was going to happen because of the incident. Ava in turn, after a few brief moments of shock shook her head and gave Evalyn an apologetic smile and a laugh. "These things happen around Hogwarts." Boyd began, rotating her shoulders and taking in a breath of air before beginning to lean forward. "You get used to it." And then she was off, blasting forward at incredible speed and seizing Evalyn by her collar in the split second after she began running. A short, astonished gasp emit from Evalyn as she was dragged along quite effortlessly in their meteoric path to catch up to Amelia.

"Hold it hold it hold it!" Ava yelled, peeling to a stop beside Amelia's procession and releasing Evalyn to instead grab her partner by the upper arm and stop her. "At least tell me what's going on!" Amelia looked over as if snapped from a trance, her pale blue eyes meeting Ava's determined green. "He has to pay" she replied in a bored, matter-of-fact tone. "It would be rude if he doesn't." Amelia added, her words giving Ava all she needed to hear to know what she needed. With that she loosened her grip and instead used her hand to pinch her brow. "Fine, let's go." And with that, off Amelia and Ava would go, following the flames to do who-knows-what with the person spreading them. In the distance Evalyn could hear all the man's screaming still, fading away as he ran further and further into Hogsmeade. Part of Evalyn was deeply curious as to what was going to come of it, but a primal, instinctual feeling also told her that it'd be best to leave it to those two and meet up with them later.

Some things were best left to the professionals.