All the other first years were staring in awe of the castle, but not him.
The moment Harry had entered the grounds, his head had been filled with a deep baritone voice, singing a dark but alluring song, to which he couldn't make out the words. The voice went silent when the large group of first years entered. Instead a ratty looking hat began to move the tear that seemed to form a mouth. The hat then began to sing.

"Oh you may not think I'm pretty,
But don't judge on what you see,
I'll eat myself if you can find
A smarter hat than me.

You can keep your bowlers black,
Your top hats sleek and tall,
For I'm the Hogwarts Sorting Hat
And I can cap them all

There's nothing hidden in your head
The Sorting Hat can't see,
So try me on and I will tell you
Where you ought to be.

You might belong in Gryffindor,
Where dwell the brave at heart,
Their daring, nerve, and chivalry
Set Gryffindors apart;

You might belong in Hufflepuff,
Where they are just and loyal,
Those patient Hufflepuffs are true
And unafraid of toil;

Or yet in wise old Ravenclaw,
if you've a ready mind,
Where those of wit and learning,
Will always find their kind;

Or perhaps in Slytherin
You'll make your real friends,
Those cunning folks use any means
To achieve their ends.

So put me on! Don't be afraid!
And don't get in a flap!
You're in safe hands (though I have none)
For I'm a Thinking Cap!

A thousand years or more ago
When I was newly sewn,
There lived four wizards of renown,
Whose names are still well known:

Bold Gryffindor, from wild moor,
Fair Ravenclaw, from glen,
Sweet Hufflepuff, from valley broad,
Shrewd Slytherin, from fen.

They shared a wish, a hope, a dream,
They hatched a daring plan
To educate young sorcerers
Thus Hogwarts School began.

Now each of these four founders
Formed their own house, for each
Did value different virtues
In the ones they had to teach.

By Gryffindor, the bravest were
Prized far beyond the rest;
For Ravenclaw, the cleverest
Would always be the best;

For Hufflepuff, hard workers were
Most worthy of admission;
And power-hungry Slytherin
Loved those of great ambition.

While still alive they did divide
Their favourites from the throng,
Yet how to pick the worthy ones
When they were dead and gone?

Twas Gryffindor who found the way,
He whipped me off his head
The founders put some brains in me
So I could choose instead!

In times of old, when I was new,
And Hogwarts barely started,
The founders of our noble school
Thought never to be parted.

United by a common goal,
They had the self-same yearning
To make the world's best magic school
And pass along their learning.

"Together we will build and teach"
The four good friends decided.
And never did they dream that they
Might someday be divided.

For were there such friends anywhere
As Slytherin and Gryffindor?
Unless it was the second pair
Of Hufflepuff and Ravenclaw,

So how could it have gone so wrong?
How could such friendships fail?
Why, I was there, so I can tell
The whole sad, sorry tale.

Said Slytherin, "We'll teach just those
Whose ancestry's purest."
Said Ravenclaw, "We'll teach those whose
Intelligence is surest."

Said Gryffindor, "We'll teach all those
With brave deeds to their name."
Said Hufflepuff, "I'll teach the lot
And treat them just the same."

These differences caused little strife
When first they came to light.
For each of the four founders had
A house in which they might

Take only those they wanted, so,
For instance, Slytherin
Took only pure-blood wizards
Of great cunning just like him.

And only those of sharpest mind
Were taught by Ravenclaw
While the bravest and the boldest
Went to daring Gryffindor.

Good Hufflepuff, she took the rest
and taught them all she knew,
Thus, the houses and their founders
Maintained friendships firm and true.

So Hogwarts worked in harmony
for several happy years,
but then discord crept among us
feeding on our faults and fears.

The Houses that, like pillars four
had once held up our school
now turned upon each other and
divided, sought to rule.

And for a while it seemed the school
must meet an early end.
what with duelling and with fighting
and the clash of friend on friend.

And at last there came a morning
when old Slytherin departed
and though the fighting then died out
he left us quite downhearted.

And never since the founders four
were whittled down to three
have the Houses been united
as they once were meant to be.

And now the Sorting Hat is here
and you all know the score:
I sort you into Houses
because that is what I'm for.

But this year I'll go further,
listen closely to my song:
though condemned I am to split you
still I worry that it's wrong,

Though I must fulfil my duty
and must quarter every year
still I wonder whether sorting
may not bring the end I fear.

Oh, know the perils, read the signs,
the warning history shows,
for our Hogwarts is in danger
from external, deadly foes

And we must unite inside her
or we'll crumble from within
I have told you, I have warned you...
let the Sorting now begin."

After a much lengthier than usual song, McGonagall opened her equally as lengthy scroll and began reading out the names of the first years.

"Abbott, Hannah"
"HUFFLEPUFF"
"Bones, Susan"
"HUFFLEPUFF"
"Boot, Terry"
"RAVENCLAW"
"Brocklehurst, Mandy"
"RAVENCLAW"
"Brown, Lavender"
"GRIFFINDOR"
"Bulstrode, Millicent"
"SLYTHERIN"
"Finch-Fletchly, Justin"
"HUFFLEPUFF"
"Finnigan, Seamus"
"GRIFFINDOR"
"Granger, Hermione"
"GRIFFINDOR"
"Longbottom, Neville"
"GRIFFINDOR"
"Malfoy, Draco"
"SLYTHERIN"
"O'Hallery, Shannon"
"HUFFLEPUFF"
"Potter, Harry"

There was a quiet murmur from everyone before the sorting hat spoke aloud

"Potter, Potter, Harry Potter,
Is it to Griffindor or Slytherin you totter?
Both brave and cunning, sly and fair,
But to both houses, you are heir.
Like your father, you can be trouble,
But like your mother, plan on the double.
Though you're smart, you are no Raven,
And with the Badgers, you'll find no haven.
Are you a snake with a lions face,
Or a lion running at a snakes pace?
What's this inside your head, a hymn?
It had better be SLYTHERIN!"

Then there was silence. Complete and utter silence. You could have heard a pin drop. Then he heard the singing again, and he was alone with the voice, entranced. The silence was broken as Slytherin began to clap and cheer.

He was ripped away from his trip down memory lane by a startling realization. It had been many years since that day, the singing had always been there, when he was sad, in his dreams, and even in the final moment when he'd killed the Dark Lord. And now, only now had he finally, FINALLY figured out why that beautiful baritone voice was so familiar. It belonged to the Dungeon Bat, though now that he had died, but still remained, he was known as the Phantom of the Dungeons. Snape had been singing to him all these years. It made sense though. Snape always seemed to just be there when he started singing. He wasn't sure if it would still work after the man's death.
Well, there was only one way to find out.

HARRY
In sleep he sang to me,
in dreams he came . . .
that voice which calls to me
and speaks my name . . .

And do I dream again?
For now I find
the Phantom of the Dungeons is there -
inside my mind . . .

SNAPE
Sing once again with me
our strange duet . . .
My power over you
grows stronger yet . . .

And though you turn from me,
to glance behind,
the Phantom of the Dungeons is there -
inside your mind . . .

HARRY
Those who have seen your face
draw back in fear . . .
I am the mask you wear . . .

SNAPE
It's me they hear . . .

BOTH
Your/my spirit
and your/my voice,
in one combined:
the Phantom of the Dungeons is there
inside your/my mind . . .

SNAPE
In all your fantasies,
you always knew
that man and mystery . . .

HARRY
. . . were both in you . . .

BOTH
And in this labyrinth,
where night is blind,
the Phantom of the Dungeons is there/here
inside your/my mind . . .
SNAPE
Sing, my Angel of Music!

HARRY
He's there,
the Phantom of the Dungeons . . .

SNAPE
I have brought you
to the seat of sweet music's throne . . .
to this kingdom where all must pay homage to music . . .
music . . .

You have come here, for one purpose, and one alone . . .
Since the moment I first heard you sing,
I have needed you with me, to serve me, to sing, for my music . . .
my music . . .

Night-time sharpens, heightens each sensation . . .
Darkness stirs and wakes imagination . . .
Silently the senses abandon their defences . . .

Slowly, gently night unfurls its splendour . . .
Grasp it, sense it - tremulous and tender . . .
Turn your face away from the garish light of day,
turn your thoughts away from cold, unfeeling light -
and listen to the music of the night . . .

Close your eyes and surrender to your darkest dreams!
Purge your thoughts of the life you knew before!
Close your eyes, let your spirit start to soar!
And you'll live as you've never lived before . . .

Softly, deftly, music shall surround you . . .
Feel it, hear it, closing in around you . . .
Open up your mind, let your fantasies unwind,
in this darkness which you know you cannot fight -
the darkness of the music of the night . . .

Let your mind start a journey through a strange new world!
Leave all thoughts of the world you knew before!
Let your soul Take you where you long to be !
Only then can you belong to me . . .

Floating, falling, sweet intoxication!
Touch me, trust me savour each sensation!
Let the dream begin, let your darker side give in
to the power of the music that I write -
the power of the music of the night . . .

You alone can make my song take flight -
help me make the music of the night . . .