The Trick 'R Treater

Halloween night, a couple of years ago:

There was a costume party at someone's house. Everyone was drinking, dancing, laughing... At midnight there was an unmasking. It was sweet retarded fun. Fifteen minutes later, a biker stumbled in through the front door. No one knew her, but people were drunk enough to think she had just been outside making a call or smoking a cigarette. Remembering the unmasking, smiling faces approached her to remove the helmet. Everyone was laughing... Someone took her helmet off. Everyone was still laughing, but something was wrong. She was a normal girl, but she had such a weird face. Why was her face so weird? Suddenly the top of her head split in two. The laughter stopped. She had just been in an accident and that helmet was the only thing keeping her head together. "Trick 'r Treat?", whispered the brain damaged girl. The night filled up with screams... 

Her name was Celine. She was 21.