What a way to start a Monday! I howled at so many lines that I can't begin to list them all.
Oh what the hell, I hafta tell ya: Oddly enough, the card was met with a horrified silence, followed by exclamations of disgust and shock, particularly from the younger students and the Muggle studies professor. It wasn't as if the card was even very gory; Snape had carefully siphoned off all the blood for future use and ensured that the fatal wound was hidden at the back of the body.
and
He waved vaguely and the card came wobbling across the room, the dead Cupid dangling obscenely. Malfoy gave a small shudder as the Cupid landed on the desk with a sodden thump. Snape stared at it morosely. "Looks like I feel."
"You're not dead, old chap, just a bit squiffy."
"Am not squiffy. Am as pissed as a fart." He prodded the corpse with a finger and the Cupid stared blankly at the ceiling. A single, fat bluebottle crawled out of its open mouth and buzzed away.
Oh, and I almost forgot
"I don't think Dingle-Batchett understands the significance of a dead Cupid, old chap," Slughorn said consolingly. "Do you need all the body parts?"
The way you used all of the prompts was delightful, and they crept up on me unaware--well done!
Oh, and last of all, the name Dingle-Batchett was inspired!