Robin walked into the room thing that all the different school houses have. I cant remember what its called. She looked around quickly before pulling the small bomb out of her black robes. No one would suspect a muggle device to blow up Hogwarts. It was perfect.
Harry walked downstairs, probably sneaking out after hours again. He caught sight of Robin and blinked, surprised. "Robin?"
"DIE!" Robin screamed, pulling out her wand. "AVADA KADAVRA!"
A blinding green light shot out of her wand tip, hitting Harry strait on in the face. He didn't have time to scream before crumpling to the ground, very much dead.
Robin smirked down at him before turning her attention back to the bomb. "Hm..." She lifted her wand and whispered a spell to it, making a small flame ignite on the end. She smiled and placed it on the fuse. It lit and sparked angrily.
She dropped it and ran.
BOOOOM!
Robin miraculously escaped school grounds just in time, turning to look at the burning rubbish that used to be a magnificent castle, bringing hope to the children who wanted to learn magic. "The heir of slytherin has come!"