This is how Metroplex defeats Queen Chrysalis goes in To Cybertron and Back Again.
[The Changelings, led by Twilight, capture Starlight, Trixie, Throax, and Discord]
Twilight Sparkle: My queen, look who we found.
Queen Chrysalis: Ah. The four Equines who journied this far to save their friends.
[Queen Chrysalis uses her magic to put green slime on their feet.]
Queen Chrysalis: Unlike the same spell I used on Shining Armor, you've been quite useful to my plans, Twilight.
Starlight Glimmer: You won't get away with this!
Trixie: We won't allow you.
Thorax: They're both right.
Discord: What he said.
Queen Chrysalis: [chuckles] I think that is unlikely to happen.
Starlight Glimmer: But...
Trixie: You have to listen!
Thorax: Free the captives!
Queen Chrysalis: Always defiant to the end, aren’t you? At every turn you have thwarted my efforts to rule Equestria as its queen. [As Queen Chrysalis is talking, everyone fails to notice Metroplex rising outside to free his friends] No more. This day it all ends. Once and for all.
[As Queen Chrysalis prepares to finish off Starlight, Trixie, Throax, and Discord, Twilight notices Metroplex outside raising his hand to tear the roof off]
Twilight Sparkle: My queen, look out!
[Metroplex rips the roof off the Changeling castle. Every Changeling backs away in fear. Princess Celestia, Princess Luna, Princess Cadance, Shining Armor, Twilight's friends, Starlight, Trixie, Throax, and Discord watch in amazement.]
Queen Chrysalis: Stop running you fools. Stand and fight!
[ Queen Chrysalis fires at Metroplex, who raises his fist to bring it down on Queen Chrysalis]
Queen Chrysalis: NOOOOOOOOOOO!!!!
[Metroplex brings his fist down on Queen Chrysalis and raises it back up]
Queen Chrysalis: [groans]
[Metroplex brings his fist down on Queen Chrysalis thrice, killing her.]
Starlight Glimmer: Leave. NOW.
[Twilight looks at Queen Chrysalis' corpse and at Metroplex]
Twilight Sparkle: Changelings, Queen Chrysalis has fallen, betrayed by her pride. I, Twilight Sparkle, am your leader now. Changelings, retreat and bring Queen Chrysalis' corpse.
Changelings: Yes, your highness.
Starlight Glimmer: Twilight!
Twilight Sparkle: This isn't over. Come Trypticon.
Trypticon: As you command, Twilight Sparkle.
[Starlight watches in horror as Twilight, the Changelings, and Trypticon leave]
Starlight Glimmer: No!
Twilight Sparkle: Oh, I almost forgot. Trypticon, bring me the Dark Spark.
Trypticon: Yes, Twilight Sparkle.
[Trypticon gets the Dark Spark and brings it to Twilight]
Twilight Sparkle: The Dark Spark. With this, I shall resurrect Queen Chrysalis.
[Shining Armor tries to reverse Chrysalis' spell, but before he could, Trypticon smacks him away with his tail]
Princess Cadance: Shining!
Trypticon: You should've joined the Changelings when you had the chance, Mi Amore Cadenza.
Princess Cadance: No! I would never after what you did to my sister-in-law.
Trypticon: So be it. When you and your sister-in-law meet again, you are enemies.