Avalane of the Flying Cactus

“Why, by the white of Merlin's beard, did you use a cactus?” Kalliope shouted as she bounded down the stairs, three by three.
“It seemed like a good idea at the time!” Avalane called from somewhere behind her.

They were in hot pursuit of a flying cactus. The potted desert plant soared through the corridors, flapping its thick, spiny, branch arms as it screeched “CHEESE” at the top of whatever it used for lungs. Along the way, it dropped toasted bread crumbs and melted cheese off its spines.
According to Avalane, she had been trying to transfigure a cactus into a grilled cheese sandwich, but something went horribly wrong.
“What spell did you use?! Neither grilled cheese sandwiches nor cacti have any kind of bird characteristics.” Kalliope skidded into an abrupt about face as the reckless plant/bird turned a sharp corner and made a break for the courtyard.
“I can't remember... it seems to be fairing pretty well with those arms,” Avalane panted.
“I think... by this point... they're wings...” Kalliope searched for the wayward cactus as she stopped to catch her breath. “There it is! It's making a break for it, outside! Get it!”
The two girls took off after the cactus again. Not watching the corridor, Kalliope crashed broadside into a Slytherin girl, heading back to the dorms after class.
“Who the... What!?” was all the girl managed to get out before the Ravenclaw plowed her over. Avalane, was was neither watching the corridor nor Kalliope, smacked into both girls as they tried to stand.
Getting up a second time, Kalliope said, “Hey look, I'm sorr... D'Arcy! It's you. Come on! You can help us catch it!”
D'Arcy was dragged along, still confused about what exactly they were supposed to catch.
“... so as soon as it got transfigured, the bloody thing took off and we've been trying to catch it ever since.” Avalane filled D'Arcy in about their plight.
“It'll wake the dead with that maniacal screeching,” Kalliope replied as the girls jumped around the courtyard after the cactus.
“Chase it into a corner,” D'Arcy said. “I'll try this counter-spell that I heard Rose Delancy suggest to some girl.”
The Slytherin that turned her cat into a frog?” Kalliope asked.
D'Arcy nodded and took aim. It missed. So did the second and the third. The frantic cactus thrashed about so, that D'Arcy's shots couldn't keep up.
D'Arcy fired again.
“Whoa, Dar! That one almost took off my ear!”
D'Arcy ignored the Ravenclaw and slowly crept toward the cactus while it perched on the brick wall, it's pot tottering precariously.
D'Arcy and company were silent as they stalked they quarry. Just a few inches closer and D'Arcy will have a clean shot. She slowly raised her wand...

“THINK FAST!!” a blur of black, green, and glass beads shot out from between the pillars.
The cactus, startled, shot needles into the air and took off in the direction of the Forbidden Forest, flying too high and too fast to catch. As it got further away, the shrieking of “CHEESE CH-CHEESE” grew more and more faint.
D'Arcy whipped around, pointing her wand dangerously, “Iyou! I swear on my box of candy I'm gonna fry you for that!”

To Be Continued...