Harry walked into Potions, hauling his books onto his desk and sitting down.  Professor Severus Snape stood in front of the class.

"Potter," Snape said. "Your twelve-inch essay assigned last week was eleven and three-quarter inches.  I do not tolerate slackers, Potter."

Some of the Slytherins laughed, and Harry slid down in his chair.

"Potter, I am so disappointed in you."

"Sorry, sir," Harry mumbled.  It was all he could say.

"Now," Snape said, "Today in class we will make a Brain Stimulating Potion, causing everyone, no matter how dumb they are-" He glanced at Neville, who quivered slightly "-to be genius for ten minutes.  Turn to page three hundred and twelve in your books and follow the instructions."

After around a half hour of brewing potions, Harry had finished his and was watching Neville.

It all happened quickly.  Neville slipped, tipping the table his cauldron was on, sending the brown liquid that was his potion flying through the air.  Harry gaped... and some of it went into his mouth.

Harry tried to spit it out, but suddenly found himself a foot or so higher, standing at the front of the classroom, behind... Snape's desk?!  He looked around the classroom to find himself.

Oh, no...

He had become Snape.

Which meant...

Snape was him.

"Potter!" Snape-in- Harry's-body yelled.

The room was quiet as everyone looked at Snape (in Harry's body).

"Wait a second," Hermione said. "Why'd you call yourself 'Potter'?" She then found a puddle of Neville's potion on the floor. "Oh, no.  This is bad.  Professor Snape and Harry switched brains.  You see, Neville added too much wormwood, causing-"

"I don't care what it causes!" Harry (in Snape's body) yelled. "I just want to be me again!"

"Quiet, Potter," Snape growled.

"It's freaky, looking at myself."

"Just because you are in my body does not mean you have my priveleges!  Five points from Gryffindor!"

"Wait a second.... shouldn't I be able to do that, then?  You can speak Parseltongue, then... you have all of my abilities and I have all of yours."

Snape sighed. "I believe so, then."

***Later that Day***

Potions had been after dinner, and it was Harry's last class, so he headed to Gryffindor Tower, finding the Fat Lady.

"Password?"

"Reducto."

The portrait swung aside, and Harry walked into the Gryffindor common room.

It had been full of talking, but everyone got silent,  They watched Harry (in Snape's body) walk through the common room.

"It's okay.  It's me, Harry!  Harry Potter!" Harry said.

Katie Bell, bent over a table, doing homework, was brave enough to say, "No, it's Severus Snape."

"I am Harry James Potter, a Gryffindor who hates Severus Snape." Harry said.

Ron Weasley stood up from his place reading the Daily Prophet at a couch. "Harry, what type of Bertie Botts' Every Flavor Bean did Dumbledore get at the end of last year when you were in the hospital wing?"

"Earwax," Harry said.

"It's him!" Ron announced to the Gryffindors. "It's Harry!"

"So, Harry," Seamus Finnigan said curiously, "Can you give us Gryffindors some points?"

"Well," said Harry, "Most likely, but someone'll have to check in the Great Hall to see if it works, to see if the hourglass of rubies for Gryffindor gets filled up."

"Well," said a first year girl with thick glasses and messy brown hair, "I left a book down there.  I could go watch the hourglass to see if it gets any fuller."

After a few minutes, Harry (in Snape's body) said, "Fifty points to Gryffindor!"

The girl came back up with her book and a smile. "Yeah, it worked!"

Maybe being Snape... at least for a little while... isn't so bad, Harry thought with a smile spreading across his face.

Harry Potter, in the body of Severus Snape, walked down the hallway of Hogwarts.  Students looked at him, scared.  Nearly everyone who was not in Slytherin either feared or hated Snape... or both.  And only the Gryffindors knew that Harry and Snape had switched bodies.

"Professor Snape, I promise I'll turn in the essay tomorrow," pleaded a first year boy whose hands were shaking.

"I'm Harry Potter," Harry said. "Professor Snape and I switched bodies.  And I'll make sure you get an O for Outstanding."

A smile spread across the boy's face. "Really?  You're not Snape?"

"No...."

Harry smiled, walking away, until he ran into... himself?

It took him a minute to comprehend this.  It was Snape in Harry's body.

"Potter, I told Professor Dumbledore and he did not believe me."

"Who would?  You look like me.  Dumbledore usually believes me, but not when I say something that far-fetched.  Perhaps he'd believe someone in your body."

"Oh, no, Potter.  No, you're not."

"Do you want to switch back to your own body or what?" Harry yelled.

"Just because you're in my body doesn't mean you can yell at me, Potter!"

"Give me a chance!"

"Fine.  But, I'm just telling you... I keep a close eye on the House points.  I know what you did."

"I didn't do anything!"

"Right, so the other teachers just so happened to give your House that many points between 6 PM last evening and 7 AM this morning, right now."

"Well.... sort of."

"'Sort of.'" Snape repeated this in a simpering tone. "If you keep talking like this to me, do you know what I'll do?"

"What?"

"It's a Quidditch match today, Potter!  I'll play in your place while using some potions that you do not yet know to knock you out."

"And?"

"I'll allow Slytherin to win."

"Oh, no.  This is crazy."

"Oh, no, Mr. Potter.  It's not crazy.  It's what I'm going to do."

"Professor Dumbledore!" Harry, in Snape's body, ran into Dumbledore's office, having recieved the password from McGonagall (who thought he was Snape).

"Yes, Professor Snape?"

"No, no, I'm Harry Potter!"

"The real Harry Potter came in earlier, claiming to be you, Severus.  Now you come up with this story?"

"I am Harry James Potter, son of-"

"Severus, everybody knows Harry's name and his parents' names."

"I told you- I'm not Severus.  I'm Harry.  Harry Potter."

"How do I know that?  How can I tell that?"

"Sir, Neville added too much wormwood to a potion, causing it to... er... not exactly... do what it was supposed to."

"Well, if you were Snape, I'd be ashamed that you knew that little about potions."

"So you believe that I'm Harry?"

"Let us call in whomever is in Mr. Potter's body, also," said Dumbledore thoughtfully.

*** 5 minutes later ***

Snape, in Harry's body, entered the office. "Yes?" he asked.

"Are you Severus?" asked Dumbledore.

"Yes."

"Why are you Severus?"

"That boy Longbottom ruined a potion by adding far too much wormwood, causing the bubbles in the potion to pop and the potion to become too thick, not to mention changing its chemical properties."

Dumbledore nodded. "I believe you now."

"Really?" Snape and Harry asked at once.

"Yes," said Dumbledore, "if what you say has happened to this potion, it should be wearing off within five minutes."

Harry smiled.  He'd be happy to be in his own body.