The song is from season 9 episode 8 of MLP:FiM.
♫ Lyrics for the song:
( You can support the show here: https://itunes.apple.com/us/tv-season... )
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[Cozy Glow]

I think I know a way that we can grow
Time to try something new, something better
No more solo, trust is the way to go
And all we need to do is work together

Lord Tirek: Ah, please!

No thanks, no way, I feel the need to say
I'm smarter, stronger, and I don't need you two

Queen Chrysalis: Ha!

Stronger? Okay, I guess we'll downplay
How bad you got your rear end handed to you

[Cozy Glow]

It's time to try a better way to be bad

Lord Tirek: [groans]

[Lord Tirek and Queen Chrysalis]

Do we really need a better way to be bad?

[Cozy Glow]

United as one

[Queen Chrysalis]

Teamwork? Please, what a fad

[Cozy Glow]

Combine all our strength, we'll go to any length
Once we have a better way to be bad

Let's go, begin, this time we're gonna win

[Queen Chrysalis]

The ice you're on is thin, so watch what you say

[Cozy Glow]

I know you're in, I think I see a grin

[Lord Tirek]

For all this pain and torture, I swear you'll pay

[Cozy Glow]

This time, we've got a better way to be bad

[Lord Tirek and Queen Chrysalis]

Sounds like a long shot, this "better way" to be bad

[Cozy Glow]

United as one, we'll make those ponies so sad

[Lord Tirek]

If we say "okay", would you just go away?

[Cozy Glow]

Once we have a better way to be bad

We want to break their friendship
We want to make them weak
You want revenge on Starlight
You want that huge physique

So let's increase our chances
By working as a team
To crush our enemies to dust
And laugh as they all scream!

All: [laughing evilly]

[Lord Tirek]

I think I see a better way to be bad

[Queen Chrysalis]

Just put me in charge, make me queen, you'll be glad

[Cozy Glow]

No! Listen to me, I'm the best of us three

[All]

Then you'll see a better way to be bad

[tempo increases]

Cozy Glow: Wait!

This is my thing, a better way to be bad

[Queen Chrysalis]

You shall do as I command, I will rule this triad!

[Cozy Glow]

Hey! This is my song!

[Lord Tirek and Queen Chrysalis]

Sorry, not any longer!

[All]

A better way to be bad

[Cozy Glow]

Now you're making me mad

[Lord Tirek]

Won't the ponies be sad?

[Queen Chrysalis]

That would make me so glad

[All]

Now we've got a better way to be baaaaaad!

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"My Little Pony" is owned by Hasbro,
"MLP: Friendship is Magic" is created by Lauren Faust.