This is how Defeating the Fallen goes in Friendship is Magic Part 2.
[The ponies, Autobots, and Toa enter the castle]
Applejack: Whoa. Come on, Twilight, Optimus, and Tahu. Isn't this what you've been waiting for?
Bulkhead: Yeah. What are you waiting for, Prime?
Onua: Come on, Tahu.
[They find the Elements of Harmony]
Twilight Sparkle: The Elements of Harmony, we've found them. Careful, careful!
Optimus Prime: And it took all working together to get us here.
[Pinkie counts them]
Pinkie Pie: One, two, three, four... There's only five!
Smokescreen: Yeah. That's weird.
Lewa: That is definately weird.
Rainbow Dash: Where's the sixth?
Arcee: I was thinking the same thing.
Gali: That was on my mind too.
Twilight Sparkle: The book said: when the five are present, a spark will cause the sixth Element to be revealed.
Optimus Prime: Yeah.
Tahu: Me too.
Applejack: What in the hay is that supposed to mean?
Bulkhead: I was thinking the same.
Onua: As was I.
Twilight Sparkle: I'm not sure, but I have an idea. Stand back. Tahu, Optimus, and I don't know what will happen.
Optimus Prime: That includes you, Autobots.
Tahu: And you, Toa.
[They turn to concentrate]
Applejack: Come on now, y'all. They need to concentrate.
Bulkhead: Yeah. Come on, guys.
Onua: Let's move.
[Applejack, Bulkhead, Onua, Fluttershy, Ratchet, Kopaka, Pinkie Pie, Smokescreen, Lewa, Rarity, Bumblebee, Pohatu, Rainbow Dash, Arcee, and Gali turn around. As they head off, a dark purple liquid flows to the platform and picks up the Elements]
Twilight Sparkle: Aah!
Optimus Prime: By the Allspark!
Tahu: What the?
[The ponies, Autobots, and Toa hear the noise]
Everypony: Twilight! Optimus! Tahu!
[The liquid slowly lifts the Elements]
Twilight Sparkle: The Elements!
Optimus Prime: We can't let the Fallen take them!
Tahu: Come on!
[They both shut their eyes and leap into the liquid as it vanishes, taking them and the Elements with it as the others arrive]
Onua: What's going on?
Rarity: Where did they go?
Bumblebee: [beeps] (translation: Where are they?)
Pohatu: How did...?
Pinkie Pie: What happened?
Smokescreen: What in the Allspark...?
Rainbow Dash: What's going on?
Arcee: That is weird.
Gali: It's all too weird.
Applejack: Twilight, Optimus, Tahu, where are you?
Bulkhead: Where could they be?
Onua: I'm not sure.
Bumblebee: [beeps] (translation: Look, you guys!)
Pohatu: Over there!
[They see a flash in the room nearby]
Applejack: Come on!
Bulkhead: [transforms] You heard her. Roll out!
Onua: Follow us.
[In the room nearby]
[Tahu, Optimus, and Twilight land on the floor]
The Fallen: [laughing evilly]
[They keep trying]
The Fallen: You're kidding. You're kidding, right?
[They ignore him and keep trying]
Twilght Sparkle: Just one spark. Come on, come on.
Optimus Prime: We can do this!
Tahu: Don't give up!
[The Fallen watches]
The Fallen: No. No!
Twilight Sparkle: But... where's the sixth Element?!
Optimus Prime: It will come! Keep trying!
Tahu: Don't lose hope!
[The Fallen laughs as he blows them back and shatters the Elements]
The Fallen: You little fools! Thinking you could defeat me? Now you will never see your princesses or your precious moon. The day... will last... for eternity! [evil laugh]
[Tahu, Twilight, and Optimus hear their friends coming and a spark ignites in their eyes]
Twilight Sparkle: [gasp] You think you can destroy The Elements of Harmony just like that? Well, you're wrong, because the spirits of The Elements of Harmony are right here.
Optimus Prime: And so are their partners.
Tahu: And their Toa!
[The Fallen gasps]
The Fallen: What?
Twilight Sparkle: Applejack, Bulkhead, and Onua, who helped us when we were in doubt, represent the spirit of... Honesty! Fluttershy, Ratchet, and Kopaka, who tamed the manticore with their compassion, represent the spirit of... Kindness! Pinkie Pie, Smokescreen, and Lewa, who banished fear by giggling in the face of danger, represent the spirit of... Laughter! Rarity, Bumblebee, and Pohatu, who calmed a sorrowful serpent with a meaningful gift, represent the spirit of... Generosity! And Rainbow Dash, Arcee, and Gali, who could not abandon their friends for their own hearts, represent the spirit of... Loyalty! The spirits of these five ponies, Autobots, and Toa got us through every challenge you threw at us.
Optimus Prime: Exactly.
Tahu: That's right!
The Fallen: You still don't have the sixth Element! The spark didn't work!
Twilight Sparkle: But it did! A different kind of spark. I felt it the very moment I realized how happy I was to hear you, to see you, how much I cared about you. The spark ignited inside me when I realized that you all... are my friends!
Optimus Prime: Mine too!
Tahu: Mine too!
[The Element of Magic appears]
Twiight Sparkle: You see, Fallen, when those Elements are ignited by the... the spark, that resides in the heart of us all, it creates the sixth element: the Element of... Magic!
Optimus Prime: Power of the Elements, come to us!
Tahu: Help us stop this villain!
[The Elements turn into necklaces and the Element of Magic turns into crowns and the ponies, Autobots, and Toa form a heart shape which ignites a rainbow beam which strikes the Fallen, creating a rainbow tornado around him]
The Fallen: Nooo! Nooo!
[Twilight, Optimus, and Tahu shoot white eye beams at him. The light fades and the Autobots, Toa, and ponies can be seen on the floor]
Rainbow Dash: Oh, my head.
Applejack: Everybody okay?
Bulkhead: I'm fine, AJ.
Onua: Me too.
Rarity: Oh, thank goodness.
Bumblebee: [beeps] (translation: I'm glad that's over.)
Pohatu: Me too.
Fluttershy: Why Rarity, it's so lovely.
Rarity: I know! I'll never part with it again.
Bumblebee: [beeps] (translation: My paints grown back.)
Pohatu: My metal! It's back!
Fluttershy: No. Your necklace. It looks just like your cutie mark.
Ratchet: And Bumblebee's looks just like his symbol.
Kopaka: And Pohatu's looks a like a symbol of his Earth wielding!
Rarity: What? Ooh. So does yours.
Bumblebee: [beeps] (translation: And yours, Ratchet.)
Pohatu: And yours, Kopaka.
Ratchet: By the Allspark.
Pinkie Pie: Look at mine! Look at mine!
Rainbow Dash: Aw yeah.
Applejack: [to Optimus, Tahu, and Twilight] Gee, guys! I thought you were just spouting a lot of hooey, but I reckon we really do represent the elements of friendship.
Princess Luna: Indeed you do.
[Princess Luna appears before them]
Twilight Sparkle: [gasps] Princess Luna.
Optimus Prime: You're back!
Tahu: That is so reliefing!
Princess Luna: Twilight Sparkle, Optimus Prime, and Tahu, my best friends, I knew you could do it!
Twilight Sparkle: But... you told us it was all an old pony tale.
Optimus Prime: And to think we thought you were speaking the truth.
Princess Luna: I told you that you needed to make some friends, nothing more. I saw the signs of the Fallen's return and I knew it was you who had the magic inside to defeat him, but you could not unleash it until you let true friendship into your heart. Now if only another will as well. Megatronus Prime!
[Megatronus wakes up]
Princess Luna: It has been a thousand years since I have seen you like this. Time to put our differences behind us. You were meant to make sure my moon was in perfect position, my friend.
Twilight Sparkle and Rainbow Dash: Friend?
Princess Luna: Will you accept my friendship?
[Megatronus thinks and hugs Luna]
Megatronus Prime: You're right! I'm so sorry! I've missed you, Princess!
Princess Luna: I've missed you, too.
[Lewa, Smokescreen, and Pinkie Pie burst into tears]
Pinkie Pie: Hey, you know what this calls for? A party!
Lewa: Come on
[At Ponyville, everyone celebrates. Twilight, Optimus, and Tahu watch and suddenly feel sad. Princess Luna looks at them]
Princess Luna: Why so glum, Tahu? Are you not happy that your quest is complete and you can return to your world?
Twilight Sparkle: Well, I think he desires to stay.
Optimus Prime: Don't you, Tahu.
Tahu: I do.
[They look at him]
[Princess Luna smiles]
Princess Luna: Spike, take a note, please.
[Spike brings out a pen and a piece of paper]
Princess Luna: I, Princess Luna, hereby decree that Tahu and his two friends will stay here in Ponyville to study friendship.
[Spike finishes writing and the crowd cheers]
Twilight Sparkle: Oh thank you, Princess Luna! Tahu, Optimus, and I will study harder than ever before.
Optimus Prime: [smiles] We sure will.
Tahu: I can tell.
[The episode ends]