Here's how the Princesses send Mako and Spencer to spy on Tirek in Thomas' Place as a Prime.
[the next day, our heroes have been called to the main hall]
Toby: What's going on Princess?
Princess Celestia: Tirek has returned.
Brian: OH NO!! THAT'S TERRIBLE!!
Peter: Well if he comes here, I'm gonna do this. [kicks Brian for no reason] Road house.
Vinny: If it was that easy, we would've done so before.
Eddy: So what are we gonna do?
Rarity: Of all of the worst things that could happen. This is the worst POSSIBLE THING!
[then the Diesel Squad races in]
Dash-9: Princess! We saw Tirek!
Kraken: He came into Diesel City and began eating crystals he's found all aorund the city!
Edd: Hey, weren't you the diesels who killed that giant Decepticon?
Pincher: Man, you may be a smart guy, but you can't even remember us?
Edd: Can't remember?
Scor-Brein: But anyway, Tirek's already grown to the height of 17ft!
Spongebob: Princess, how are we gonna stop Tirek?
Princess Luna: The way we did before, drain his power, decapatate him, then kill him.
Fix-it Felix: Pardon me Princess Luna, [takes off his hat] but do you think we should send someone to find Tirek and find out his plan?
Mucker: Felix has a point. If we don't know Tirek's plans, what are we to expect?
Princess Luna: We don't know ethier
Princess Celetia: What about Twilight?
Uray: I don't think we should send an Equine, Tirek may feel their presence. We should someone else, but not a retired villain. Like last time.
Princess Celestia: Good point.
Princess Luna: Who else?
Mako: [waves his fin] I volunture! I'm too cartoon crazy, and physics defying for Tirek to feel my presence.
Princess Celestia: Very good Mako.
Princess Luna: But, we should send someone else to help you. It won't be easy to do it on your own.
Princess Celestia: Spencer, you will help.
Spencer: Me? Why me?
Princess Luna: Cause Tirek has never seen you before.
Gordon: I was hoping she would say me.
Bill: Maybe Spencer and Gordon hate each other?
Ben: No they don't.
Bill: Yes they do.
Ben: No they don't.
Bill: Yes they do!
Ben: No they don't!
Princess Luna: [in royal canterlot voice] STOP IT!!!!!
Skyla: Mommy, what do you think Tirek is manly after?
Cadance: I don't know sweetie.
Mucker: Spencer, before you go. Take this. [shows a case]
Spencer: What is it?
Mucker: [opens a case] Your own weapon.
Mako: Right, I'll take one side, and you take the other.
Spencer: Okay shark, let's roll.
[the 2 leave]
Gordon: [in Obi-Wan's voice] I hope he doesn't do anything foolish.
Henry: I don't know about that, but he's not that dumb Discord.
Gordon: It's not that, he doesn't know Tirek like any of us do.
Brian: I'm with you, Gordon.
Peter: Let's hope he's doing is right. Like that time I had to pull some boards off an old barn.
Peter: [is pulling the board but is straining]
Pepper Clark: Pull it harder, Peter!
Peter: [Straining] I'm...doing...my..best! [The board cracks] Whew, that was a tough one.
Pepper Clark: [Laughs] Can he fix it? pLaughs]
Brian: Yes, he can Pepper. Haven't you got work to do?
[It goes back to the present]
[out somewhere in Equstria]
Mako: Okay, must find Tirek.
Spencer: Right, let's split up.
[the 2 do so]
[somewhere out in Equestria, Mako is searching]
Mako: Alright, monkey head. Where are you?
[Mako searches high, low, near, and far. But he desn't find anything, until he hears something]
Mako: Tirek! [he gets up on a ledge and watches Tirek]
Tirek: Soon I'll get that Matrix and then I will start up Megatrain's machine and his army will be mine! [cackles] But first I must increase my power [picks up a few crystals and eats them, then he grows to the height of 28ft]
Mako: Oh no! I gotta tell Optimus! [he quietly leaves Tirek and then races for Canterlot castle]