The Smooze from the G1 movie is reimagined as the S'muz, an omnicidalEldritch Abomination that seeks to devour the multiverse and absorb the psychokinetic energy it believes other life-forms have "stolen" from it, is gleefully willing to torture anyone that gets in its way, and refuses to stop until it's the only thing left in all of existence.
There's also MatronHydia, whose attempts to try and free the S'Muz are the driving force of the story. She knows what it's capable of, and that's exactly why she wants to free it, as she falsely believes that she can control it and use it to destroy her enemies. She finally crosses the Moral Event Horizon when she sacrifices her own daughter Draggle in order to complete the summoning ritual.
Nightmare Fuel: Everything about The S'Müz, it reaches almost Giygas levels of malevolence and the way it kills is graphic. Just try to get through the last 10 pages of chapter 4 without flinching, poor, poor Draggle.