Josie
A term for a person (usually used for females only) who is one or all of the following: 

A) Unreasonably violent. 
B) Nice one minute, then suddenly lashes out in anger (though usually in a comic fashion). 
C) Secretly mafia. 
Example for A or B)
Person 1: (Is hit by person 2) Ow! You're such a josie, you know!
Person 2: (hits them again) 

Example for C) Omg, have you heard? She's been a josie all along! 