Credit: MTV

It looks like "A" isn't the only one the cast of Pretty Little Liars needs to worry about anymore. It turns out Ashley Benson is the one terrorizing her castmates behind the scenes!  

On this week's all-new episode of MTV's 10 on Top (airing Saturday, August 10 at 12:30 p.m. ET/PT), stars Tyler Blackburn and Shay Mitchell dish on which of the show’s cast members is the biggest prankster on set. And if you know these PLL stars like we know them, then it probably didn't take you very long to realize that the pretty little prankster in question was Ashley! But watch out, Ash: If you mess with Shay's gorgeous locks, you're going to be in big trouble! 

Watch the exclusive clip from the episode below to find out what pranks the PLL cast play on set. (Spoiler alert: Get ready for some major Haleb feels.) 

Did you know Ashley was such a prankster? Watch this week's 10 on Top for more scoop from your favorite PLL stars, plus interviews with Victoria Justice and Nelly, only on MTV

Credit: MTV Photo: Pretty Little Liars' Tyler Blackburn and Shay Mitchell Talk Pranks on MTV's 10 on Top! — Exclusive Video