I was on around on some minecraft pree-release server I found, looking for a strong hold with ender eyes when i found a a giant underground room that looked as though it was carved out of TNT. In it i found a ton of signs altogether showing this: 

Ah, distinctly I remember the eyes I gained,
from each seperate dieing ender wrought its perls upon the floor.
Eagerly I wished to dive; - into that black abys
From from the beasts I had sought to borrow, borrow rods
From the rare and radiant beasts whom the devils named - Blaze
Nameless there for evermore.

And then silken sad uncertain rustling of each step I took
Thrilled me - filled me with fantastic terrors never felt before;
So that now, to still the beating of my heart, I fell falling
into that dark abys i remember - Dark and falling stars was all.
Some fear I felt granting me power to survive that fall,.

Presently my soul grew weaker; hesitating then no longer,
I opened my eyes to a dark and grainy sky
Dim vales- and shadowy floods, horrible looking creatures whose forms we can't discover.
For the tears that drip all over!
no moons at all - every moment of the night-
Forever changing places-
And they put out any star-light
With the breath from their black faces.
Deep into that darkness peering, long I stood there wondering, fearing,
Doubting, dreaming dreams no mortal ever dared to dream before;
But the silence was unbroken, and the darkness gave no token,
And the only word there spoken was the whispered name, `Ender skull!'
This I whispered, and an echo murmured back the name, no the creature, `Ender skull!'
quit frankley all was fear, merely this and nothing more.

Back to the portal turning, all my soul within me burning,
all I sall was darknes somewhat brighter than before.
`Surely,' said I, `surely those are eyes of purple;
Let me see then, what thereat it is, and this mystery explore -
Let my heart be still a moment and this mystery explore; -
'TIS A SKULL APON THAT ENDER, AND A CROWN OF PEARLS FROM MINIONS SLAIN BEFORE!'

now my eyes fully open sall a twighlight rider apon a dragon, stacked apon heaps on glory
tis the one named Enderskull
here I ran from the beast, demons king.
Towers of obsidian and castles of bedrock passed me by
Screeming lies never thought posable before
when, with many a flirt and flutter,
In there stepped the stately beast with the white skull of yore.
Not the least obeisance made he; not a minute stopped or stayed he;
But, with mien of lord or lady, perched far above my head
Perched upon a tower of obsidian
Perched, and sat, and nothing more.

Then this ebony skull beguiling my sad fancy into smiling,
By the grave and stern decorum of the skull it wore,
` thy travaler here shall die,' said the beast
"art sure no craven, nameless now for evermore
Ghastly grim and ancient dragon wandering from the nightly cliff -
Tell me what you mean to do, slay my dragon for glory?'
Quoth the skull, `Nevermore.'