This is how Twilight's Flashback goes in The Return of Dragon Twilight.
Twilight Sparkle: Optimus?
Optimus Prime: Yes?
Twilight Sparkle: Can we talk?
Optimus Prime: Of course.
Twilight Sparkle: Well, I've been having these flashbacks of my past as Dragon Twilight recently.
[Twilight starts having a nightmare. As she sleeps, her body parts start transforming into Dargon Twilight's body parts]