This is how Equines meet the Autobots goes in Darkness Rising Part 1.
[At the Wonderbolts Academy, a blue, rainbow-maned Pegasus pony named Rainbow Dash is training]
Spitfire: Nice job, Rainbow.
Rainbow Dash: Thanks, Spit.
Billy: Hey, check it out. If it isn't our old friend, Rainbow Crash.
Spitfire: Hey back off!
Hoops: What are you gonna do? Try and make us?
Spitfire: I would if I could!
Rainbow Dash: I'll leave you guys to it. [flies away]
[Rainbow Dash finds Arcee in motorcycle form]
Rainbow Dash: Hello beautiful. I'm gonna own a ride like you one day.
[She gets on]
Arcee: You have gotta be kidding.
[She sees the Vehicons behind her]
Arcee: [realizing it was a trap] Scrap!
[She drives off, Rainbow Dash still on her]
Vehicon #1: Starscream, target acquired. Accompanied by a female Equine.
Starscream: [comm] What is it with Autobots and Equines?! Destroy them both!
[Vehicons start shooting at them.]
Arcee: Hold on.
Rainbow Dash: Who said that?
Arcee: Well, it certainly wasn't a talking cloud.
Rainbow Dash: Why are those guys shooting at us?
Arcee: There is no us. And they are no guys.
Rainbow Dash: What are you?
Arcee: I don't exist. Tell anyone about me and I'll hunt you down.
Rainbow Dash: Okay.
[Bumblebee arrives and rams the Vehicons]
Rainbow Dash: Friend of yours?
[At the boutique, a white, purple-maned Unicorn pony named Rarity is working on some dresses]
Rarity: [grabs her phone] Hey, mother. Yes. Lives good. Okay. Talk soon. Bye.
Arcee: This ends here, Cons.
Rarity: What are they?
Rainbow Dash: Talking cars that can turn into robots or the other way around.
[Arcee is nearly beaten by the two Vehicons]
[Before the Vehicons could get Arcee, Bumblebee arrives and transforms and lands on one of the Vehicons and punches the other one. Bumblebee steps on something and realizes its one of Rarity's dresses]
[Bumblebee looks at Rarity]
Bumblebee: [beeps] (translation: I'm sorry.)
Rarity: Don't worry. It's okay.
[We see a black police car