My roommates girlfriend is a piece of [censored]

[skates]

You 100% need to get out of this situation. Speaking to her won't do anything, odds are Ty's the only person with that capability. Tell him she's banned from the apartment, but odds are that won't do anything because of you not having balls in the past and him not believing you'd actually talk to the landlord about it. Once that option is wasted, either bite and apply to move into on-campus housing, or consult psych. options for her. Get her into mandatory counseling or something and hope that the result pisses her off enough to get out of there. Speaking to her parents is also solid, but with anything like that, you run the serious risk of having her trash your stuff (I hope you have a lock for your room... if not, install one).

Credibility: I have no balls. I spent 6 months *helping* someone with degenerative behavior only to be forced to hospitalize her for psych reasons.