Any of Lady Gaga's hairstyles would be really. Remember when she used real meat as hair accessories? You could buy rubber or plastic meat and attach it to your head. Most people would never dream of wearing meat hair accessories.
Also, that crazy hair bow was cool although that was a clip-in hair piece.
One of my friends one year went as the game Candyland. She did her entire head as candy. She used licorice and lollipops to completely decorate her hair. The only problem? She wore it to a Halloween party and people were snatching the wrapped candy out of her head and eating it. LOL.
Good luck with your Halloween hair.