A/N : I thought about this fic, based on book Five's Boggart scene with Molly Weasley.
-THE INVERTED BOGGART
"Oh please Severus! You just do it out of grudge against Gryffindor!" said a furious McGonagall.
"Well, I resent that implication!" Snape replied, sarcastically. "If I did it, it was because they deserved it, you know how Gryffindors can be... cheeky."
With that, he looked at her as if implying she was the Number One cheek of all.
McGonagall shot him the coldest and most disgusted glare. Her lips thinned and her nostrils flared. She felt she could kill him!
Snape had, in just one day, taken 500 points from Gryffindor and to top everything, he was walking around with that smirk on his face after Slytherin had defeated Gryffindor at the Quidditch match that morning.
She couldn't stand the man!
'If he says one more thing, I'm going to wipe that smirk off his face!' she thought.
They were in the staff room and when the few other teachers there saw the argument coming, they fled the scene as fast as they could. It was an ordinary thing to see McGonagall having these rows with Snape and the best thing was to stay out of the way.
At that moment Filch entered the room followed by Mrs. Norris, in his usual bad mood.
"Professors, there seems to be a problem in the Girls’ Bathroom on the second floor!"
"What problem, Argus?" sighed McGonagall, impatiently sinking into a chair.
"It seems they found an entertainment and I'm having trouble keeping them out of there! After the rumour spread throughout the school, the bathroom is swarming with them bloody students!" said Filch.
"What rumour?" Snape was getting interested.
"An inverted Boggart."
"A what?" both Snape and McGonagall asked in unison.
"It beats me! Never heard of anything like it, but the blasted thing is turning the second floor into a circus. I can't keep them out of there all by myself, you know?" Filch’s voice faltered in irritation.
"What on earth are you going on about?" Snape was now scowling.
"The students are having fun with the thing! It seems it turns into something you desire instead of something you fear. I was hoping you could get rid of the thing, Professor."
"Ok, let's see what this is all about," said Snape, going for the door.
McGonagall was following them when Snape stopped on his heels and turned to face her; his curtain of hair gracefully covering half of his face. "You can leave that to me. I am perfectly capable of getting rid of a Boggart."
"Oh, I'm sure you are, but apparently this is not an ordinary Boggart and we don't know what we are dealing with," the Headmistress rebuted.
"All the more reason to leave it to me. What with your age and being a woman…" He measured her up with disdainful black orbs.
McGonagall opened her mouth but no sound came out, she seemed to be searching for words, her eyes were bugging out and, her hands were closed into fists. "How dare you... you ... get out of my way, you great bat!"
She fumed out of the room, leading the way to the second floor. "I'm going to show him... who does he think he is... the nerve ..." she was muttering all the way to the Girls' Bathroom as a very amused Snape followed, slowly enjoying the effect of his previous comments.
As McGonagall arrived at the bathroom's door she could already hear the giggles. She pushed the door and saw a group of giggling excited girls making a circle around something. The Transfigurations Professor approached them immediately, only to see the girls staring at who appeared to be Malfoy.
She was about to ask him what he was doing in the Girls’ Bathroom when there was a loud "Poof!" and he turned into Harry Potter. More giggles.
By this time Snape and Filch had arrived and were watching in disgust as the girls got more and more excited with the Boggart's appearance.
"Poof!"... Gilderoy Lockhart... "Poof!"... the Weasley twins... "Poof!"... Dean Thomas... "Poof!"... Colin Creevey... "Poof!"... Potter... Malfoy... Lockhart... Lupin...
"Lupin??" spat Snape aggravated. "Alright, enough! Everybody out!"
There were disappointed groans across the room as the girls left reluctantly.
"Argus! Stay outside and don't let any student come in until I sort this thing out," the Potions master snarled.
McGonagall crossed her arms with a skeptical look on her face and waited to see what he could do.
Snape squared his shoulders and prepared to point his wand at the Boggart when "Poof!" it turned into an Order of Merlin First Class award.
McGonagall snorted. "Oh my, is that your deepest desire? How predictably dull!"
He looked at her and sneered. "Ha - Ha!" Then turned to the Boggart and yelled, "Riddikulus!"
The award shook a little bit but nothing really changed.
"If the Boggart is inverted, it's obvious that the spell has to change! We have to find an opposite spell," McGonagall said, quietly and pleased at his failed attempt.
"Well, then it's all yours," he said, stepping aside and extending his arm in the Boggart's direction.
McGonagall thought, rubbing the tip of her finger on her chin. A moment later, She confidently stepped in front of the Boggart, wand at the readyto cast the spell when... "Poof!"
Snape's eyebrow shot way up as a sly grin formed on his face.
Still smiling he said silkily, "Oops... is that your deepest desire? How… unexpected."
McGonagall's cheeks grew terribly red. She couldn't move at first, just staring in utter shock. Recovering herself, she cleared her throat and with a shaky voice whispered the spell that hopefully would vanish the sight in front of her for eternity. "Gravis Agrimoni!"
The Boggart swirled a bit and disappeared in a light gray smoke.
McGonagall turned slowly and not facing Snape, finding it better to admire the tip of her boots, said, "See, I told you I could... now If you'll excuse me, I have a class."
She headed fast for the door and almost bumped into Filch.
Snape chuckled and said to himself, "That ought to keep her out of my hair for a while."
McGonagall ran down the stairs to her class. She was going to try and avoid Snape as much as she possibly could, and luckily he wouldn't touch the subject.
Otherwise she had no idea how she would explain why the Boggart had turned into... Severus Snape.