Again, again!

There were so many people trying to accomplish the same task that sometimes it was hard to concentrate on a single ball. A few times he'd gotten one in his sights right before somebody else had stolen it from him with their own spell. Not cool.

Olly moved on to a different one, moving quickly as soon as he'd chosen his target. Wand in the air, concentrating on his intent. "Arresto Momentum." He waved his wand sharply. The ball he'd been pointing at slowed and Olly grinned. He waited a few seconds until it got close enough for him to snatch out of the sky. As soon as he could, Olly tossed it into the Slytherin bun. Then he turned his gaze back to the falling balls, ready to do it again.