Often they are 12 year olds
They will stop at nothing. If they think you even remotely look like Robbert Patterson (aka Edward Cullen), regardless of how far fetched the absurd idea, they will hunt you down like a pack of dogs and attempt to rape you.
Be particularly careful when you hear a fan girl yell "Surprise!" because they will most likely charge at you and rape you but because they yelled surprise its perfectly legal.
see surprise buttsecks
Unwilling look alike: wtfbbq? gtfo!
Twilight Nazi: SURPRISE! *pounce*