We all go a little "Crazy" sometimes, especially while trying to figure out Pretty Little Liars.

But just how crazy is Mona? That was one of the questions posed/teased on last night's new installment, which featured the eerie return of this mental institution patient.

What can fans expect from next Tuesday's "Stolen Kisses?" Major trouble for Aria and Ezra, if the following ABC Family promo is to be believed, along with a new discovery. What could it be? Watch and take your best guess now:

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.