Disclaimer: Characters owned by J K Rowling, obviously. The Mirror, imagined/owned by myself.

Summary: For everything in this universe, there is an opposite. Yin and Yang, Fire and Water, Light and Dark. So, for the Mirror of Erised, that shows you the deepest and most desperate desires of your heart, surely there must be an opposite? Beware, for when you look into the Mirror of Cosmaruri, you will see the darkest, most terrible nightmares – you will see whatever you fear the most.

WARNING! This story will contain SLASH, as in two blokes, in love. You have been warned.

The Mirror of Cosmaruri

Myctophobia

It had been a long and trying day for Severus Snape. The very first lesson of the day had been Third Year Gryffindor versus Third Year Slytherins – a near impossible class to teach by any Professor's standards. On top of that, he'd had to break up yet another fight between Malfoy and Potter. No – between Malfoy and Weasley. Potter hadn't actually been anywhere in sight until Snape showed up, and then he'd actually helped stop Weasley from beating Draco to a bloody pulp. Snape frowned. That was the fifth time this week that he'd found the two boys arguing, and it was only Wednesday! Something's happened there. Something drastic has changed the dynamics of the Golden Trio. Maybe Weasley has taken it upon himself to scourge the school of as many 'Death Eater Bastards' as he can find. I'll probably find that it was all Potter's idea. I have no doubt that he's the mastermind behind this whole thing…

Snape frowned, trying to think back and remember if Potter had been behaving suspiciously as of late. Unfortunately, as hard as he tried, he couldn't fault Potter's behavior. In fact, if anything, Potter had been more quiet and well behaved than usual – staying out of any intercations with the Slytherins, and paying attention in Potions. Hm. Suspicious. It's always the quiet ones…

Glaring, Snape continued to stalk down the corridor towards his office, his hand clenched around his wand as though it were Potter's neck. Stupid boy, causing me trouble! If only I could just find proof, then Dumbledore would have to-

Snape's inner musings were cut short as he rounded the corner, and stopped dead.

There was a child sitting on the floor outside his office.

How strange…

Bewildered, Snape took a step forwards and cleared his throat. The black-haired boy gave no response, save for a tightening of bony white fingers that were fisted in his hair. His knees were drawn up to his chest, his bare feet flat on the floor, toes curled up under the soles of his feet, almost as though he were trying to disappear in on himself.

Snape frowned and coughed again. No response. The Potions Master's eyebrows rose, as he took in the grey muggle tracksuit bottoms and the red, oversized t-shirt, hanging loose and baggy over thin, slightly shaking shoulders.

A Gryffindor.

Snape shook his head, nonplussed. This was unheard of! No Gryffindor would dare to sit outside the Potions Master's office – especially after curfew! It was practically suicidal – a guaranteed months worth of detention at a minimum. No student could possibly hope to get away with such ludicrous behavior! Snape was just working himself into a fury when he realized two things.

One, the boy was in fact crying, teardrops splashing to the already damp stone at his feet.

Two, there was only one Gryffindor brave – or foolhardy – enough to ever dare to approach Snape, because there was only one Gryffindor who had the Headmaster wrapped around his little finger – and there was only one Gryffindor who knew of his identity as a Light Spy. In fact, there was only one Gryffindor stupid and selfish enough to risk compromising that position. There was only one Gryffindor who could possibly be sitting there.

"Potter?!"

This got a reaction. Potter froze, his breathing suddenly far too rapid and shaky for Snape's liking. He carried on, regardless.

"What the devil are you doing outside my office, Potter?! It's well past curfew, and you're no Slytherin, in case you'd forgotten!"

Snape was so disturbed and shell-shocked that he completely forgot to deduct any points. This, however, did not seem to give Potter any comfort. He just sniffed, and refused to look up. Snape could almost smell the fear radiating off him – and was that blood on the boys hands?!

Something has happened to him. Something terrible has happened. Snape was suddenly filled with a sickening sense of dread. What could possibly have happened to Potterto make him so afraid?! He should be safe, here in Hogwarts! Snape stood in silence for a couple of seconds before reaching a decision. If the castle had been breached, if they'd already got to Potter, and turned him into a sniveling shadow of the hero he was supposed to be, then it was over. All the planning, the spying, the war strategies, the preparations… It was all over, all for nothing. If they've got to Potter…

Then we've lost.

Everything I have fought for…

It's all for nothing.

It's over.

Snape blinked and ran a hand though his hair, before letting it fall limply to his side. He cleared his throat again, his mouth dry, and his mind whirling.

"What… What happened to you, Potter? Was…" He cleared his throat again, not wanting to ask, not wanting his suspicions to be true, because if they were… No. It was unthinkable, it just couldn't… Couldn't have been… But maybe… "Potter, was it Him? Was it the Dark Lord?" The words were like bitter poison on his tongue, and he waited, tense, for the answer.

The answer that never came. Potter just let out a slight whimper, and a few more tears fell, shattering on cold stone. Snape signed, and asking himself what the hell he though he was doing, he sat down quietly next to Potter. He heard the smaller boy's breath hitch in surprise, and then-

Snape froze. He'd never been any good at comforting people, and now Potter – Harry bloody Potter – had flung his arms around Snape's neck and was sobbing his little Gryffindor heart out.

Snape should have yelled. He should have deducted points, issued detentions, expulsions, hexes, and curses… Anything to get this blasted boy off him. But…

He… he sounds like her when he cries. This stray thought was so heartbreakingly unexpected that Snape could do nothing but sit there, remembering a moment long ago, the only other time when someone had willing turned to him for comfort. He closed his eyes, and suddenly, the tears soaking through his robes were hers, and the arms around him were pale and freckled, and the soft hair under his chin was hers, red and flaming, like silken rubies. The sobs were hers, desperate and desolate, and the heartbeat was hers, and he could feel her, hear her, smell her soft scent, of shampoo and rainwater, and… and…

Lily…

Snape could feel his breath catch in his throat, his eyes burning. He forced himself to pull away, and look down, his eyes falling upon the face of his enemy, his tormentor. But instead of reveling with joy at the sight of a tearful James Potter, all Snape could see were her eyes, big and green, shimmering emeralds swimming with tears, like forest leaves dripping with rain, or blades of wild grass, sparkling with dew. Snape stared into her eyes, and he could remember, her tearful voice, pleading with him, begging him to stay with her. To stay and to comfort, to keep her safe.

And just like then, Snape had no idea what to say. Her unexpected, undeserved trust was broken, as he sat there in silence, stone-cold silence, and let her walk away from him, tears of betrayal and disappointment still falling from her eyes.

Snape wholly expected Potter to give up and walk away too, to run back to Gryffindor Tower, to find someone else, someone deserving to confide in, who knew exactly what to say, and then later laugh, laugh at the memory of his hated Potions Master sitting helplessly on the floor, silent, shaken and lost.

Eventually, however, Potter's breathing evened out, and he pulled his arms away. But he didn't leap up, didn't laugh, and didn't run. Instead, he sighed mournfully and scrambled slowly to his feet. "I'm sorry, sir." Potter's voice was raw and painful to hear, as though he'd been screaming.

"I… I didn't… I just… I just found myself here, I didn't… I didn't plan this. I just… I was just here, and then you were there, and… and… I just… I'm… I'm really…" Potter's voice hitched and dropped to a hoarse whisper. "I was just so afraid, sir."

Snape frowned, forcing his thoughts out of the past, his fears about the Dark Lord rushing back. He let out a long, slow breath, and motioned for Potter to come back and sit down. Potter just stood there, slightly hunched over, covered in innumerable bloody scratches, his eyes wide and fearful. Snape snarled slightly. "Sit, Potter! I am not going to hurt you!" Potter continued to stare at him, terrified and mistrusting, and Severus could feel his heart breaking at the sight of her eyes looking at him with such an expression. "Potter! Stop looking at me like that, and sit! For Merlin's sake, Potter, stop it! Just stop it! I can't bear it, Potter!" I can't…

There was a moment of silence, in which Severus could've sworn his stomach fell out of his boots, and he shrank to being about two feet tall. Eventually, Snape just sighed and tipped his head back, his eyes falling closed. If he was going to hell, he may as well do the job thoroughly. "What happened to you, Potter?" he asked again. Silence. "I am assuming that my position as a spy has been discovered, as I was not aware that an attack had been planned. I didn't know of any plot, any… I was not informed of the Dark Lord's intentions. If I had, Dumbledore would have been able to take precautions. You are still safe here, Potter. It will all be fine. We can get you some protection, something…" He trailed off, suddenly too tired to even speak.

Thankfully, Potter finally spoke. "It wasn't Him, Professor." Snape's head snapped up. All… All is not lost?!

Potter snorted and rubbed his eyes tiredly. "As if Voldemort could scare me!" Snape frowned. It was true, Potter had faced the Dark Lord and lived – but he would have to be a fool not to be afraid. Snape was suddenly very afraid for the boy's sanity as he laughed derisively.

"He's nothing but a snake-faced, monstrous half-blood who lives his life following the destiny he's given. I… I who choose my own destiny… I have nothing to fear from him."

Snape was speechless. "Potter. You… You know about the prophecy?!" Potter froze, before shrugging and nodding slowly.

"Yeah. Dumbledore told me at the end of last year after… After…" He trailed off, and for some strange reason, Snape could feel a pang of sympathy for the boy.

"After Black died." Potter flinched and nodded.

"Yeah. That. Anyway, I know now. I know… I know what I'm supposed to do. I know what Dumbledore expects me to be. I… know that it's my fault, sir. It's because… It's because of me that He's done all this. That's why it's up to me to make it right. To be the hero. To atone for all my sins." Snape stared at Potter, his mind spinning. The boy's eyes were wide and feverish and his unhealthily pale face was flushed with two spots of red. His breath was coming in furious gasps, and a solitary tear escaped down his cheek.

"Potter," Snape enunciated clearly, "Don't be so obtuse. Of course it isn't your fault! No one thinks that it is! Good Merlin, Potter, you're just a child – and an orphan child at that! A Gryffindor orphan! What harm could you possibly do to anyone?"

Potter inhaled sharply, and turned away to wipe his eyes. "But sir," Potter mumbled on, his voice muffled by his shirt sleeve. "You blame me, don't you? After all, its… it's my fault that she died. It's my fault that you lost her."

Snape gasped and leapt to his feet, betrayal stinging bitter and sharp in his heart. "How…" His voice was for the first time in memory shaky, and afraid. "What has Albus told you?! Did he tell you this?!" Harry blinked, and took a step backwards, shaking his head wordlessly. Snape saw red. He grabbed the front of Potter's shirt, and slammed him back against the dungeon wall, and practically roared, "LIAR! WHO TOLD YOU, POTTER?! WHO TOLD YOU THAT?! WHO TOLD YOU ABOUT THAT?!" His eyes glinting manically, spit spraying Potter's face. Miraculously, Potter managed to choke out an answer, and prevent Snape from killing him then and there.

"I… Hogwarts told me! It was Hogwarts, she told me!"

Snape blinked, his anger fading to a cool pink mist instead of the mind-stifling red thunder-clouds from seconds ago. He didn't let Potter go.

Oh god… He's actually insane…

Harry licked his lips nervously. "Well, sir, you see… Sometimes… Sometimes when I can't sleep, I go for a walk, to clear my head. And… I… It's the castle, sir! The castle's alive! I can hear it, the flow of magic, and the whispers of the house elves… And sometimes, sir, the ghosts talk to me. And the portraits. Mostly about the funny things that they've seen in their time, and the gossip. But… Sometimes, if I've had a particularly rough day, then… Somehow, they know. And then… Then they tell me about my parents." His voice broke, but he soldiered on. "I… I think it was the Grey Lady who told me, in the end. She said… She used to see you studying in the library sir. She said… She said my mother… My mother was your only friend, sir. And… I… I look the spitting image of the man who took her away from you. I can understand, sir. I can understand why you hate me. I'd hate me too you know."

Snape was speechless.

Eventually, from somewhere he dredged up enough sense to actually speak. "Five points." He saw Harry stiffen indignantly, but carried smoothly on, his voice still quiet and confused. "To Gryffindor House. For discretion. And though it was not asked for, nor indeed deserved, it appears I should award another five points for an exceptional ability to empathize."

The look on Potter's face was priceless.

"T…Ten points?!" He spluttered. "Are… Are you okay, sir?!"

Snape snorted again. "I will be, Potter. Once I've woken up and this bizarre semblance of reality turns out to be nothing more than a very odd, whiskey-induced dream." Potter let out a startled chuckle before swaying slightly, and sitting down with a thump. Snape instantly paled, and knelt next to Potter. "Potter? Potter, what is it?" It was then, with an ice-cold trickle of dread that Snape realized that other than the fact that it wasn't the Dark Lord, he had no idea what had led Potter to him in this state in the first place. "Potter, what happened?!" Potter looked up at him, his eyes dim.

"I… It was a mirror, sir."

A Mirror. Snape knew instantly what the boy was talking about. That goddamn mirror. I told Albus, must've told him a thousand times – it will find him. And when it does… It will destroy him. He opened his mouth to say something – anything – but Potter beat him to it.

"It's okay though, sir. It… It doesn't matter. Just… Just forget I was ever here, okay?" Snape snorted.

"That's bullshit, Potter. You can't be okay, not after seeing The Mirror of Cosmaruri. No one's ever okay after that." Harry stared at him, disbelief evident on his face. "Not even me."

"You?" Potter breathed incredulously. "You've seen it?!" Snape nodded, and sat down properly, leaning backwards.

"Well, I don't think either of us will be getting to sleep any time soon, not if you've seen what I think you have. So, sit back Potter, and for once in your life, listen." Potter sat back, his face pale, but his eyes alert and showing no signs of sleepiness. "It was years ago… The day I received the Dark Mark. It was in my sixth year of school, just after Halloween. Around the fifth of November. I don't remember precisely – those days have become a bit of a blur, a haze of nightmarish unknowing. Anyway, it was late, and I snuck back into school after the Initiation Ceremony. I was exhausted, but there was no way I could've slept. Not after that. So I decided to take a walk to, ah, clear my head." He heard Potter snicker next to him, but continued regardless. "I found myself wandering along the Third Floor Corridor – with which I remember you to be particularly acquainted. It was through the same door, in fact, as the one through which you found the trapdoor to the Philosopher's Stone, and?" He paused, and Potter got the hint.

"The Mirror of Erised," he breathed.

"Exactly!" said Snape triumphantly. "You see, Potter, those rooms which we charmed – they weren't actually there. They were called upon to appear if they were needed. In other words, they only existed when someone was looking for them. Do you see, Potter?" The boy nodded, and Snape continued. "There are hundreds of rooms like that in this castle, the most powerful of which is the Room of Requirement. That gets inside your head and gives you what you want or need. The other rooms… They contain only previously designed and created rooms, charmed to appear when they're called upon. In the case of the Mirror of Cosmaruri… Well, I did some research, and found little information. Not many people escape that Mirror, Potter. It's a Mirror, designed to reveal whatever people fear the most. It is the complete opposite of the Mirror of Erised – the Mirror of Desire. This is the Mirror of Nightmares. In the end, most people are driven insane – or just drop dead on the spot, either by fear or by their own terrified hand. Anyway, I digress. I was sixteen years old, as you are now, still a child. The Mirror sought me out – it feed on power, and those with strong magical cores are drawn to it. It's no surprise, Potter, that it found you. You are, after all, the Chosen One." Potter scowled, but said nothing, still listening intently to his tale. "I wandered naively through the door, wandering where my feet were going to take me. But instead of adventures, or indeed, my own bed, I found myself looking into a mirror. But it wasn't my face that I saw." There was a pause, as Snape summoned up the courage to reveal to Lily's son just how much his mother meant to him. "It was your mother's."

Harry gaped at him, his eyes wide in surprise. Then he gulped audibly, and stammered, "Did… Did you… In the mirror, I mean, did you… hurt her?" Snape frowned, and tried wildly to guess what the boys desolate, pleading expression might mean. Maybe… Maybe he saw the same thing? Maybe he is more like you that you realize… He looked away, and spoke only one word.

"Yes."

"Did you kill her?" Harry's voice was quiet and laced with tears. Snape nodded.

"Yes."

"Did… Was it… How?" Snape shuddered slightly, unwilling to describe the horror he had seen. Potter persisted. "Was it horrible, terrible, bloody and… and…"

"Yes." There are some things that you just can't describe. How could I tell you, Potter? You of all people? How could I tell you that I saw myself grasp your mother by her lovely long hair, and slit her throat, her blood flooding out in a fountain of blackening redness. How could I tell you that I heard her screams, bubbling and gurgling and desperate? How could I tell you that I saw her eyes glaze over, her body convulse and stiffen, and collapse to the floor? How could I even begin to tell you that?!

Harry was speaking again, his voice scarcely audible even in the silent corridor. "When… When you killed her… Did… Did you… Did you laugh?!" Snape's head snapped up, and he was only mildly surprised to see that the boys face was once more streaked with tears.

"Yes." At this Harry let out a sob, and his head dropped into his hands. Snape watched him for a moment, before carrying on with his story.

"That's not all, Potter. That's not all I did. That's not the worst of it. I… I was… Disgusting. The things I did, the things I saw… Burning, bleeding, crying, screaming, dying… I can remember their faces, pleading, desperate, lifeless… I saw myself, bring chaos and destruction upon the world – at the bidding of my Master. My Lord. I saw myself, consumed by the Dark Arts, consumed by lust for power, by my will to serve, by my own wish for personal gain. I saw myself, drowning in the Darkness, evil growing, twisted and wrong inside of me. My eyes turned black, and my heart to stone. I… I… Isn't it ironic, Potter? Your Potions Master, Great Bat of the Dungeons…Deathly afraid of the Dark?"

Harry grinned wryly, and looked over at Snape. Snape just scowled back - though his eyes were glimmering with something less hateful, less bitter than usual. And Harry couldn't help but laugh. Snape's face crumpled into a bittersweet smile, and he stared at the floor, as though it held all the answers.

"Harry." His voice was quiet, and strangely gentle, causing Harry to stop laughing at once. "Has anyone ever told you? You may look like your father... But your laugh... Your laugh is entirely your mother's."

For a long time, Harry could say nothing at all. When he eventually found control enough to talk, the only words he could find to say were, "You told Voldemort the prophecy, didn't you?"

Snape went white, and could have sworn that his blood turned to ice - but he nodded anyway.

"Yes, Potter. I did." Potter stared at him, blinking.

"Are you sorry? Do… Do you wish you could go back and… Fix it?"

Snape could feel his eyes burning but managed to answer with a relatively steady voice. "With all my heart, Potter. With all my heart."

They sat together in silence, both with eyes brimming with tears – both determined not to let them fall. It was Harry who broke first, and wiped his eyes with his wrist. Snape just blinked furiously, and tried desperately to push his memories away, back to the dark corner of his mind where they were usually left to rot. There was just one thing left to say – one more thing he had to know. "So, Potter. What do you think of me now? A sad old man, who let himself become his own worst fear. I let my jealousy, my hatred overcome me – I let it destroy everything that was precious to me. I let the Darkness into my life, and look! Look! Look what I have become. I live a life that isn't even worth living." His voice rang out, bitter and flooded with loneliness.

He was startled to feel a tentative hand on his shoulder, and looked up once more into Lily's shining eyes. "Don't be stupid, sir." Harry's voice was soft and understanding. "There's always hope."

Snape shook his head incredulously. "How can YOU of all people tell me that! You, with the world on your shoulders, and your fate practically inevitable!" Harry just looked at him, sad and smiling.

"Because. Because if I let go of my hope... I would be letting go of everything. And I'm not ready to stop fighting. Not just yet."

Author's Note:

Myctophobia – A fear of darkness.

Two posts in a day! A record, I think…

Next Chapter: Tom Riddle.