The autobots and you were doing something at the medbay while Optimus was walking around outside, he discovered something on the ground, it was a purple liquid which Is dark energon, he touched it and he got corrupted, he was screaming in pain and you guys rushed over outside and saw Optimus but instead... he's body were corrupted by dark energon and he's left eye was covered in black, he covered it with his hand, looking at everyone.