To the tune of 'Mary Jane' by Alanis Morrissette, which I don't own. Nor do I own Harry Potter. Nor do I own the term 'Mary Sue'.

Mary Sue

What's the story, Mary Sue, you're a Malfoy?
And you might just be the niece of Dumbledore.
You seem to lure in all the men, it's like magic,
Cho doesn't really have a chance anymore.

You're from the States?
An author insertion.
You're far too perfect;
You're brave and smart
And you're pretty.

You charm Professor Snape so well, Mary Sue,
What's the point of going to read anymore?
You send the canonlore to hell, Mary Sue,
D'ya ever wonder what J.K. wrote it for?

Well, it's OOC, Mary,
A sad misconception;
You've a Veela's beauty,
But it's not for Snape,
With his occlumency.

Please be quiet, Mary Sue
You're annoying
Please, just leave us alone

You’re the great crusader,
We wish you'd go away.
You're smarter than Hermione,
And that's why we hate you.

You act the saviour, Mary Sue, but you're selfish,
All you really want is a cute guy.
'Cause all that matters, Mary Sue, is your ego
So get lost, my dear, goodbye…

Incidentally, I don't mind OC Malfoys, Dumbledore's nieces, American OCs, author insertions, brave, smart or pretty OCs, or Snape/OC romances.

What I do mind is people doing them BADLY!!!