A/N: I'm not usually a fan of crossovers, but I thought this might be kind of fun. So in order to read this, you need to pretend that Harry and Co. are in their sixth year at some point during the third season of House. Also, a warning: my medical expertise comes solely from the internet. So please bear with me if anything is totally incorrect.

"Hey mate, what's up?" Ron asked Harry as they headed to Transfiguration class. "You haven't been yourself lately."

"I'm fine," Harry replied.

"Are you sure?"

"Yes!" Harry snapped. "Sorry…I didn't mean to yell. I guess I just haven't been sleeping well lately."

"You're not…having those dreams about You-Know-Who again, are you?" Ron asked, concerned.

"No, nothing like that," Harry assured him. They reached the Transfiguration classroom and entered to meet up with the rest of the sixth years, including Hermione.

"We're getting our essays back," she said as soon as they had sat down. "How do you think you did?"

"Oh come on, Hermione, do we really need to stress out about every grade we ever get?" Ron asked, rolling his eyes.

"Well, considering that you failed the last one, I would think you'd be concerned—"

"Shut up!" Harry said suddenly. They both looked at him. Harry immediately regretted his outburst. "Do you two really need to bicker all the time?" he said in a quieter voice.

"Sorry, mate," Ron said, exchanging a look with Hermione. They both looked worried. Harry wanted to tell them off for being so concerned, but before he could, Professor McGonagall entered the classroom.

"Good morning, class," she said, and everyone immediately went quiet. "Today we are going to be reviewing Vanishing spells as they pertain to large animals. But first, I need someone to pass back the essays…Mr. Weasley, would you be so kind?"

Ron got up from his seat and went to the front of the class to collect the essays. As he started passing them back, Professor McGonagall opened her mouth to speak once more, but before she could, there was a loud retching sound from the back of the classroom.

"Neville!" Lavender Brown shouted, sliding her desk away from the vomiting boy next to her. Neville Longbottom was throwing up uncontrollably in the back of the classroom.

"Mr. Longbottom, are you okay?" McGonagall asked in shock. Neville lifted his head and was about to say something to her before he was silenced by another wave of vomit.

"Oh, dear!" McGonagall said. "Someone, take him to the hospital wing!"

"Wait!" Ron said. He reached into his pocket and pulled out a small, two colored candy. Ripping off one end, he gave it to Neville, who forced it into his mouth and immediately stopped vomiting.

"I thought I was eating a mint!" Neville gasped, wiping his mouth.

"Careful there, mate," Ron said with a nervous laugh. "Fred and George leave those Puking Pastilles all over the place. Best not to eat anything, if you ask me."

"Thanks," Neville said breathlessly. Professor McGonagall hurried to the back of the room and performed a Vanishing spell on the puke on the floor.

"Okay," she said. "Now that Mr. Longbottom is okay, I would like everyone to please--"

Her voice faded away as a searing pain shot through Harry's abdomen. He moaned and clutched his stomach, certain he was going to throw up just like Neville. But he didn't, and the pain intensified. Harry moaned louder.

"Harry, are you okay?" Hermione whispered from beside him. Several people heard and turned around.

"My stomach," Harry gasped. "It hurts—AHHH!" he let out a yell. The entire class was looking at him now. Harry fell off his chair, doubled up in agony. His yell turned into a scream.

"Somebody do something!" Hermione shrieked.

*CUE HOUSE OPENING CREDITS*

A/N: Okay, that was just the short teaser. The other chapters will be longer. Reviews appreciated!