Harry sat in the infirmary, impossibly bored. That was the stage of boredom you generally reached after about a dozen hours of doing simply nothing. Harry'd reached it in two. His pillow was still stubbornly ovaloid.
Harry heard a loud boom, and looked around the infirmary - half nervous, half wired. Nerves were useless things - wired was pure energy, not yet focused into doing.
"If the two of you would be kind enough to stop whispering, and allow me to start my class?" Snape's voice (in false saccharine mode) slithered through the infirmary.
It took Harry a moment to grasp the content of what Snape was saying. He wasn't here, he was in the defense classroom. And from the tone, that was Ron and Hermione. Probably concerned about me, Harry thought wryly.
"Thank you. In the future, you may learn more by keeping your mouths closed and your ears open." Snape drawled. "Speculation has a 99% chance of being useless, in my experience." Snape's eyes hardened (Harry didn't need to see to hear in Snape's expressive voice), "Or would you care to share your inane blather with the class?"
"No, sir," Ron said.
"We were wondering where Harry is, sir," Hermione said, her tone respectful even if her words were anything but.
"Has your speculation helped any thing at all?" Snape drawled, his tone patronizing.
"No, sir. Though it might in the future, as any planning ought." Hermione didn't take well to being patronized.
Harry heard the faint sounds of Professorial Robes swishing, and interpreted that as "Snape was done pestering the impudent Gryffindors, and was now heading towards the front of the classroom."
"As I was saying, you might learn more from listening than idly talking. In this case, one Mister Harry Potter has apparently decided to conduct some extra credit for Defense class." Harry didn't need to be there to see Snape's eyes turning to slits - Shite, the Defense Club! Harry had to hope that no one was as bad at acting as he was. Snape wasn't even talking about that. "At nearly six in the morning, today, Mister Potter was injured in the outskirts of the Forbidden Forest."
"Accio Contraption!" Snape continued, not giving anyone enough time to even breathe a syllable about Harry. Whatever Snape had summoned, he shook - it had a metallic rattle, dull and heavy. "How many of you know how this works?"
"A paltry five. Had any of the rest of you been accompanying Potter, you would have been injured as easily. Granger, demonstrate how this works." Snape rattled off. Although it was nice of Snape to make it seem like Harry wasn't a complete and collossal idiot for stepping into a trap, Harry was one of those who knew how they worked. It was completely stupid for him to have fallen for it.
A moment later, "Not like that," Snape hissed, urgency in his voice, "If it nearly severed Potter's leg, what do you think it might do to your arm?"
The next moment, Harry heard, "Accio Oaken Cane!" Followed by the thunk of something hitting (presumably Snape's) hand. "Here, try this."
Springing the trap didn't make a detectable noise. What did was the audible crunch of metal teeth through a wooden cane. then the louder metallic crash of the teeth clanging together.
Someone in the class - possibly Parkinson (who possessed a particularly teeth-grating laugh) screamed in Soprano.
Snape allowed it to peter out, before speaking, "What sort of magic is this?" His dark tone was mild.
Hermione let out a nervous giggle, "No magic here, sir. Just a simple machine."
Snape continued, "If it had been you, and not Potter in the woods, how would you have detected such a thing?"
Hermione paused, "Using my eyes. Which, yes, are fallible."
Snape continued, "Is there a spell for detecting such muggle equipment?"
Hermione said, "Not that I know of." I know of one, Harry thought, suddenly, That magnetism trick would have been easily able to detect it!
"Nott," Snape said.
Nott responded, "For that particular... device, I could cast a detection spell for metal."
Hermione said, quietly, "Not all muggle traps are metal."
Snape continued, "Your homework assignment, at least for the ones of you that are not indisposed, is to research Muggle traps, and write an essay on one of them. You will each choose a different trap, is that understood?"
The room erupted in whispers, before Snape's voice cut through them again. "Potter will be losing 100 points for being out of bed, out of Hogwarts, and out of bounds after curfew."
The room stilled.
"For serving as an abject lesson in understanding the tools of war, Potter has gained Gryffindor 25 points." Snape said. "Class dismissed."
Unfortunately for Harry, the sound did not cut off just then. As students scrambled out the door, it was a merry din in the normally quiet infirmary. Harry heard the grind of a door shutting, and the sounds muffled. Soon, there was another stony grind, and Harry heard Ron, whisper-shouting to Hermione, "How can he do that? Harry's hurt - isn't that enough? Does he have to take that many points?" As Harry was currently hearing from Snape's own position, his heart sunk. Ron's mouth was going to get Ron in trouble - and Ron had been trying to be polite! He just wanted to vent.
"Calm down, Ron," Hermione said, "I want to see Harry before our next class."
Snape's voice spoke smoothly, "You would do well to listen to Miss Granger's words. Patience is a virtue."
Harry listened to the swish of Snape's robes for nearly a minute, before he heard a soft, "Off."
[a/n: Yes, Snape's exaggerating where Potter was. In my AU, Potter wasn't in 'get into trouble' part of Forbidden Forest. He was merely in 'out of bounds for caution's sake' Forbidden Forest. Or at least that's what Snape says.