Actors Who Were Never The Same After A Role

She came across pretty unhinged when she debuted as Harley Quinn in 2016's Suicide Squad, but Margot Robbie apparently had a much harder time making her follow-up film, 2017's I, Tonya. Robbie's turn as vilified figure skater Tonya Harding won her plenty of plaudits, but the role seems to have come at a cost: She needed weekly MRI scans after herniating a disc in her neck, and her physical health was actually the least of her worries. The Oscar nominee got so lost in the role that the lines between work and real life became dangerously blurred at times.

"I had lost my mind," Robbie told Grazia, explaining the impact this had on her co-star, Sebastian Stan. "I genuinely thought we were these people and we were off the set, running down the street screaming at each other and the cameras are running after us. I think I was screaming something about needing to go to hospital because my hand was broken. It wasn't, but I was so caught up in the moment. And Sebastian was like, 'Margot, where are you going?' He went to pick me up because I was continuing to tear down off set and I turned and punched him in the head."

Stan portrayed Jeff Gillooly, Harding's onetime husband. According to Robbie, throwing herself into this "abusive relationship" deeply affected her. "[I] found it emotionally traumatic," she admitted (via The Hollywood Reporter).