Harry Potter Lost Chapter: Dolores Umbridge Dies

I'm a total Harry Potter fan much like everyone else, I like the newer books, but I don't mind reading the classics. I don't think I've ever read weird or messed up books before, though I don't think I want to read any after the experience I had...
I was reading the last Harry potter book that I bought from a simple flea market. This book was different.
Instantly after the book was over there were more pages. I had already read the book before so I know how odd it was. It was a secret chapter i've never heard of called Harry's Revenge.
"Harry walked through the halls to Dolores Umbridge's room, completely immersed in his thoughts.
'I'm going to kill her, I'm going to kill her' he kept repeating over and over again in his head."
NO HARRY! I thought in my own head as I read. I hated Umbridge, but I guess... Hmm, I'll keep reading.
"Harry knocked on the door, and used Alahamora to unlock it. Umbridge was sitting there, torturing Ronald Weasley.
"Can't you see I'm BUSY!!??" Umbridge shouted.
Harry said "AVADA KEDAVRA" and Umbridge dropped dead.
Ron approached Harry. 
'Bloody hell, what'd you do to her, Harry?!'
Harry didn't respond and then Stunned Ron.
'That's what I THINK, RONALD!' Harry boomed.
Then, in an instant, Dumbledore was on the scene.
'What have you done, Harold?! What have you done?! HOCUS POCUS! FLIBBERY JIBBERY!'
'Ha! That's not a real spell, old man, I just used that on Dudley--'
BOOM! The entire school had exploded. Muggles all around turned an ear. Was it a giant clap of thunder? Did Big Ben collapse? Nobody knew. It remains a mystery."
I was very scared and slammed the book closed.
"Try to keep this interesting for me, Muggle."
I turned around to see where the voice came from, and what I saw made me scream...
Sitting on my bed... staring right at me...
... Was a Harry Potter plushie, smiling with bloodstains under its eyes.