This is how Megatron introduces Dark Energon goes in Darkness Rising Part 2.
Optimus Prime: (voice) Previously on Transformers Prime: Friendship is Magic.
[Recap of the previous episode]
Arcee: Cons are back. Cliff might be in deep scrap.
[Cliffjumper gets hit and his horn comes off]
Ratchet: Cliffjumper's life signal just went offline.
Optimus Prime: As of today only we six Autobots remain on this Equestria.
Rarity: What are they?
Rainbow Dash: Talking cars that turn into robots or the other way around.
Arcee: Look, you may be in danger because you are one of the few, one of the only nine who have ever seen us.
Twilight Sparkle: Why are you here?
Optimus Prime: To protect your planet from Megatron. But if his return is imminent, it could be catastrophic.
Megatron: I have returned.
[End of recap]
[The scene cuts to Megatron and Starscream]
Starscream: Of the Energon deposits we have located while you were away, Lord Megatron, this one is by far the most significant. The drones have been mining without a pause during your absence, and have amassed quite a stockpile. [to Decepticon Miner] You there! Fetch me a sample!
Megatron: Starscream! Now that I have returned I will issue the commands.
Starscream: I understand, Lord Megatron. Then as your humble servant, shall I ready the Space Bridge to bring forth the Decepticon army you have surely gathered during your three years in space?
Megatron: My army will come. But my time away has yielded a more intriguing means of materializing them. The solidified form of the matter the ancient texts referred to as the Blood of Unicron!
Starscream: Unicron the Destroyer. But it is said that his blood is the Anti-spark!
Megatron: Plucked from cosmic shores, gaze upon Dark Energon.
Starscream: Legend tells that it holds the power to revive the dead.
Megatron: We require only a cadaver to be certain. Are you willing to make the ultimate sacrifice?
Starscream: Hehehe, ahem, that may not be necessary. If I may, Lord Megatron?
[Decepticon Miners drag in Cliffjumper's corpse]
Starscream: Consider it a welcome-home present.
[Transformers Prime: Friendship is Magic]