It be more brutal if Unicron use his psychic powers. It hurts enough punching or crushing. But a mind-zap on the brain hurts more; especially because of how the brain is the centre of all nerves. Since Unicron’s sadistis, I see him doing the mind-zapping slowly and with torturous pain for his pleasure. And it be mroe brutal if he reveals his motive was they outlvie their use; showing he only saw them as his pawns and had zero intent to keep his promises. And if he snorts coldly to Optimus Prime, Optimus Primal, the Mane 6, and some human allies going righteous angry with how he uses others as pawns and betrays them once their use be done. It also rock if some manage to push his buttons by comparing him to Primus who’s mroe virtuous and keeps his promises.

@Background Pony #49D4
Well, Twylight might want them dead. Everyone wants to hurt and kill those who do wrong. But that’s the thing. Righteous ones such as the Mane 6 know such a feeling is wrong. It takes great strength from morality.
It rock if Unicron try to tempt the Mane 6 includign Twylight to take revenge, and if they refuse. Twylight admits her bitterness to Chrysalis for the wedding incident including when she use her brother against her, Tirek for using Dyscord and for the emotional pain including the destruction of her house, and Cozy Glow for using her and others. But instead of killin ghtem, she knows its wrong to kill. A good lesson to audience members how acting on revenge is wrong and makes you no better than your enemies.

@Background Pony #6EFA
Wrong clueless, Twilight never wanted them dead just seal them away for their crimes. You just don’t like Twilight for your own selfish reasons.

Twylight: You slew them.
Unicron: You want them dead.
Twylight:I zero did.
Unciron: You did> I saw so. Even without my psychic powers.
Twylight: Yes.
Sunny Starscout: It’s zero wrong to feel anger. Only to act on such.
Unicron: sentimental as Primus, Prima, Solus Prime, Optimus Prime, and Optimus Primal. Your compassion for the weak shall cause your fall as it did for Sentinel Prime and Apelinq.

It be more brutal if Unicron killed them with mind powers. ANd more so if he mind-zap them on their brains, the most important organ. A slow and tortuous death. A big way to show his sadism. ANd also show the virtues of the heroes inlcuidng Optimus Prime, Optimus PRimal and Primus such as their rigtheous disgust.

I picture the sassy ponies commenting how it was low for Unicron to crush them after how they helped him and react on anger when Unicron declares them usleless, shoing he sees them as inferiors instead of equals as Primus. Helps show they’re opposites; Unicron thinks he’s above them all, and Primus sees them as equals.

Cannonball: what in the name of the energy way was… oh… oh primus…

Doubledealer: lockdown! ran up to lockdown visable hook arm you were a good friend… rest well in the well of allsparks

Megatron: scrap! It wiped out nearly all of our teammates!

Soundblaster: may i suggest a temporary retreat!

Optimus: right!

Armourhide (energon ironhide): thats the smarest thing you’ve said!

And thus, Lord Tirek, via the actions of Clank, killed his future self.
 
Mark Acheson, who voiced Unicron, also voiced Lord Tirek. David Kaye, who voiced Megatron, later voiced Clank in the Ratchet and Clank series.
 
@Silverdust  
Of course he’d be shocked. Not even he would want to see a poor filly be crushed into a fine paste :(

@Background Pony #4B9E  
Yeah. Even Optimus is shocked by this

That was shocking