Disclaimer: JKR owns Harry Potter and all related characters. No profit is being made from this story, and it is not intended to be a violation of the copyright. "O captain! My captain!" is a poem written and copyrighted to Walt Whitman.
10 points to whoever recognizes the Dante reference.
Story Notes: You may blame "Dead Poet's Society" for this.
"But O heart! heart! heart!
O the bleeding drops of red!
Where on the deck my captain lies,
Fallen cold and dead."
--Walt Whitman
Not my hands on the wand and not my voice as it chokes out the words that flicker green underneath a carnivorous skull, hissing from not-my wand, beware all ye who enter here. It was not designed to hurt or bleed, but I see it on my hands I see it on my face. I see red red red everywhere I turn and why does no one else see that same cruel color? I see the spots where my captain walked with scarlet footprints burning behind my eyelids and my face presses against my bloodstained hands
"O captain, my captain..."