You definitely remember Janel Parrish as Mona Vanderwaal in Pretty Little Liars, but how well does she remember the hit show? We quizzed the star of PLL: The Perfectionists on tons of PLL trivia, and things got really tricky! She says it's the hardest PLL quiz she's EVER taken. I can't wait to see what Mona Vanderwaal is up to on PLL: The Perfectionists.