Flip case 

One who is a two faced, backstabbing, freak. This is also used for dogs and children with hyperactivity disorders.

Mary, you are a friggin' flip case.
Jose! RUN! There is a flip case running toward you.
Marlene over there is a flip case.

Flip case by Fly-J June 17, 2007

flip a case 

To get a criminal case overturned by presenting new evidence, eliminating existing evidence or by preventing witness testimony. caught a case, criminal justice sytem, prosecutor, court of law, defense lawyer, cops, police, behind bars, jail, prison, 25 to life, orange is the new black, the big house, time served, court case, overturned

The only way I’m going to get out of prison time is to flip a case I got coming up for armed robbery.

flip a case by joecoolthefool December 14, 2018

flipcase 

A person who, while seeming normal, could "flip" in an instant to become their darker self. You can usually spot their intensity, boiling just below the surface.
Different from nutcase who always shows their lesser self.

"You know he's a flipcase so watch what you say."

flipcase by JohnCanon March 30, 2010