This is Unicron's arrival goes in My Little Pony Transformers Prime: The Return of Harmony.
[The Autobots and ponies except Twilight leave the spot where the labyrinth was. Thunderwing approaches Twilight]
Thunderwing: Make sure to get everything ready for Unicron's arrival.
[Twilight nods and follows her "friends"]
[Unicron watches]
Unicron: Yes. Everything is going as planned.
[Unicron rises to the surface]
[The Autobots and ponies arrive at Twilight's castle]
Applejack: I can't believe that Twilight's acting the opposite of herself.
Bulkhead: Me neither.
Pinkie Pie: This has never happened.
Smokescreen: Yeah.
Rarity: If only there was some way to turn it around.
Bumblebee: [beeps] (translation: But how?)
Fluttershy: I don't know.
Ratchet: Don't look at me.
Rainbow Dash: Whatever. Let's just get inside and think this through.
Arcee: I'm with you on that one, Rainbow.
Optimus Prime: Agreed.
[As they prepare to enter, they see Twilight standing in the doorway]
Twilight Sparkle: Girls. Guys. Glad you could make it.
[As Twilight smirks evilly, she becomes gray]
[Unicron arrives in the throne room. Thunderwing and Twilight kneel to him]
Unicron: Rise, my servants.