This is how Hiro's Transfomation goes in Do Princes Dream of Magic Nightmare Trains?.
[The film opens to Thomas and his friends chuffing through the hall of the Castle of the Royal Pony Sisters. In the throne room, Princess Luna stands in front of Hiro in his pony form with a ball of black nebula smoke behind her]
Princess Luna: [lifts her head and opens her eyes] Are you ready, Hiro?
Hiro: [lifts his head and opens his eyes] Yes. I'm ready, Luna.
Princess Luna: Then let us begin. [moves away so that Hiro now stands beneath the ball of nebula smoke]
Thomas: [arrives with his friends] Hiro, wait! You don't have to do this!
Hiro: I have to, Thomas. I must.
Princess Luna: The time has come for Hiro to face the true fears that nightmares bring.
[An eclipse happens and Hiro is englufed in a dark ball of magic. It then turns orange and Hiro bursts out, now wearing blue armor like Nightmare Moon, only he now wears a helmet. His pupils turn into slits and he grows fangs as he laughs evilly]
Princess Luna: Behold, Hiro's worst nightmare. Becoming Nightmare Hiro!
Nightmare Hiro: [laughs evilly] You were right, Luna! I didn't understand nightmare fear before! But I do now! [laughs evilly again]
Thomas: Then there's only one way to end this!
The Steam Team: Steam Team Rainbow Power Time!
[The Steam Team start channeling their rainbow power and they try to shoot Nightmare Hiro with it but he resists it and laughs evilly]
Nightmare Hiro: Your Rainbow Power can't hurt me! I'm resistant. And why? Because, of the Tantabus! [laughs evilly]
Ryan F-Freeman: Maybe not. But I'm here! [transforms into Dark Ryan F-Freeman]
[Suddenly, the Tantabus opens a hole to reality and escapes]
Ryan F-Freeman: Thomas. Go with Luna and take on the Tantabus. I'll handle Hiro.
Thomas: Nightmare Hiro! Without the Tantabus, you have no power!
Nightmare Hiro: No, It's impossible!
[The Steam Team's Rainbow Power overpowers Nightmare Hiro and he turns back into Hiro and they share a group hug]
Ryan F-Freeman: Are you ok, Hiro?
Hiro: Yes, Ryan. I'm fine.
Princess Luna: [wakes up from her dream] Oh, no! What have I done?
Rigby: What's wrong, Princess Luna?
Princess Luna: I was showing Hiro the true fears that nightmares bring but I let the Tantabus escape in the process.
Rigby: Is Ryan in it?
Princess Luna: Yes. But this is all my fault. And now, the Tantabus is going to invade everypony's dreams and turn them into nightmares.
Rigby: You're right. We need to help him.
Mordecai: What are you talking about, Rigby?
Rigby: Oh, nothing.
Mordecai: Oh, okay.
Rigby: Ok, Luna. Let's team up and stop the Tantabus!
Princess Luna: We must warn the Steam Team.
Rigby: And Ryan too.
[They race to the bedroom]
Ryan F-Freeman: Hi, Princess Luna. Why is Rigby with you?
Princess Luna: I have a very important announcement to make.
Ryan F-Freeman: Ok. What is it?
Ryan F-Freeman: The Tantabus!? We need to stop it right away.
Princess Luna: Sssssh. They'll hear you.
Ryan F-Freeman: Ok, Princess Luna.
[In Thomas' dream]
[Thomas hits a Terrorcon with his sword]
Ryan F-Freeman:[off-screen] Thomas is having fun in his dream.
[Thomas takes down another Terrorcon. But then the Tantabus shows up]
Rigby:[off-screen] That's not good. You think there will be a title of this, Ryan?
Ryan F-Freeman:[off-screen] Wait for it!
Rigby:[off-screen] Ok, Ryan.
[Thomas takes out another Terrorcon. Dark Energon spews out forming the title: Do Princes Dream of Magic Nightmare Trains?]
Ryan F-Freem: [off-screen] Now that's a title.
[The Tantabus uses its magic to turn the Terrorcons into an image of Optimus Prime]
Ryan F-Freeman: I'll stop this.[summons his Keyblade and charges at the Optimus image] Have at thee!!!
Princess Luna: Wait, Ryan! Let Optimus say what he has to say!
Ryan F-Freeman: Ok, Princess Luna. I'm always ready in case it's a fake Optimus.
Optimus Prime: I am very disappointed in you, Thomas. You never were able to protect the Blue Ruby, Black Pearl and Matrix of Leadership safe from Tirek. You weren't able to stop Unicron from invading Cybertron. And you were never able to stop the Decepticons from ruling Earth. I never should've chosen you to be a Prime.
Ryan F-Freeman: I think I waited long enough.[throws his Keyblade at Optimus which impales him] You are dead!
Thomas: Ryan? Why did you do that?
Ryan F-Freeman: That Optimus is really a fake made by the Tantabus.
Thomas: The what?!
Ryan F-Freeman: The Tantabus. Princess Luna and Rigby told me about it.
Thomas: Luna. Tell me about this Tantabus.
Rigby: I'll pull your Keyblade out for you, Ryan.[pulls Ryan's Keyblade off of the fake Optimus' chest]
Princess Luna: The Tantabus is a creature of my nightmares. It was unleashed when I tried to show Hiro the true fears that nightmares bring.
Rigby: Here we go![tosses Ryan's Keyblade to Ryan] Here, Ryan.
[Ryan catches it]
Ryan F-Freeman: Thanks, Rigby. [to Thomas] Optimus never say those awful things to you, Thomas.
[Thomas watches as the fake Optimus fades into nothing]
Thomas: So. The Optimus in my dream is a fake?
Rigby: Ryan doesn't allow you to suffer letting the fake Optimus talking to you. So he killed him.
[The Tantabus escapes]
Ryan F-Freeman: Come back here![chases after the Tantabus]
[They follow it into James' dream]
Rigby: What dream is this, Princess Luna?
Princess Luna: James is dreaming that he is famous.
Ryan F-Freeman: There's the Tantabus![summons Rusty the friendly Dalek and Mordecai] C'mon, Tantabus. Have at me!
[But the Tantabus proceeds to turn the dream into a nightmare]
Ryan F-Freeman: At least it can't hear me.[gets hit by the magic of the Tantabus and starts to transform]
Mordecai: What's Ryan doing?
Rigby: Ryan's turning into a Nightmare Moon version of himself!
Thomas: James, what you are seeing is not real.
[Ryan struggles against the magic]
Ryan F-Freeman: I'm trying, Rigby. So little time to free me. Now less. Now none!!!
Thomas: Ryan, no!! [gets grabbed by Luna]
Princess Luna: Let Ryan transform, Thomas. It's like I transform into Nightmare Moon.
Rigby: Ryan? Is that you?
Mordecai: Are you ok, Ryan?
[Ryan looks at them]
Thomas: Ryan? What happened to you?
Princess Luna: Ryan's turned into a Nightmare Moon version of himself, Thomas.
Rigby: We'll help you, James![to Ryan] C'mon, Ryan. Let's do this.
Ryan F-Freeman: Ok, Rigby. What's happened to me?
Ryan F-Freeman: I transform into who?
Princess Luna: Nightmare Moon.
Mordecai: Have a look, Ryan.[shows Ryan a mirror]
Rigby: What's wrong, Ryan?
Ryan F-Freeman: I've been turned into a Nightmare Moon version of myself. I look hideous.
Rigby: You got some style, Nightmare Ryan.
Princess Luna: That's a nice name, Rigby.
Ryan F-Freeman: Thomas. Grab James.
Thomas: Ok, Ryan. Or Nightmare Ryan?
[Thomas grabs James]
Ryan F-Freeman: What if my sister sees me like this.
Princess Luna: Who's your sister, Ryan?
Ryan F-Freeman: Sari Sumdac. She's my sister, Princess Luna.
Princess Luna: Wow, Ryan. Look like you and I have sisters. But don't worry. We'll ensure she does not see you like this.
Ryan F-Freeman: Thank you. When we stopped the Tantabus. Cody is in for a nice surprise.
Mordecai: Ryan. I think you call this form Nightmare Ryan.
Rigby: Ryan. If there's something Luna and I should know about your transformation?
Ryan F-Freeman: Well. I got some nice armor. My eyes look like Nightmare Moon's and I got wings, a horn and some nice teeth.
Princess Luna: That's nice, Ryan.
[The Tantabus escapes]
Ryan F-Freeman: Not again!
Rusty the friendly Darlek: Exterminate! Exterminate!
Thomas: After it!
Rigby: Let's get it!
[They follow the Tantabus into Percy's dream]
Ryan F-Freeman: We're in Percy's dream. Let's hope Sari isn't here. She'll be scared if she saw me like Nightmare Ryan.
[The Tantabus shows up]
Rigby: I'll stop it![jumps onto the Tantabus]
[But it shakes him off and works it's evil magic]
Ryan F-Freeman: I'll save you, Percy. Here's Nightmare Ryan!!
[Percy turns and sees the Tantabus]
[Ryan grabs him]
Percy: Whoa! Thank you, Ryan.[looks at Ryan's form and scream] What happened to you?
Ryan F-Freeman: Oh. I absorbed the magic of the Tantabus and now I transformed into Nightmare Ryan.
Percy: What!? The Tantabus?! Nightmare Ryan!?
Princess Luna: Yes, Percy. Ryan has turned into I was Nightmare Moon. Plus, the Tantabus has taken from the dream of you.
[Percy calms down]