Eldritch Abomination/Toys

"Tren Krom: You think me an alien... an "other"... But I am of the substance of this universe, and I walked here long before you or even Mata Nui himself."
 * Tren Krom from Bionicle exists as a Shout-Out to Lovecraft. However, he actually isn't an alien or other; he was created by the Great Beings just like everything else in the Matoran world. Despite this, he's got the looks -- tentacles and all -- and causes insanity in those who look upon him. He was also one of the first things to exist in the Matoran world, managing it before Mata Nui,, was activated.

- Federation of Fear


 * While we're at it, Makuta was also described like this as first- a kicking, screaming, lashing, thing of pure malevolence.
 * Of course, then he got retconned into a Magnificent Bastard Chessmaster more akin to The Devil than anything Lovecraftian, and Greg Farshtey himself has stated that he prefers Makuta this way.
 * And now there is Annona, which has been described as a small, star-like thing with tentacles and a room chilling aura. It eats dreams.
 * The first Rahi were tentacled monstrosities and other madness-inducing sea beasts. Akin tho Tren Krom, they are actually naturally occurring in the Matoran world, but they are still unspeakably ancient and strange.
 * There are Cthulhu dolls.
 * D'aww. Great, ancient evil.
 * Unicron, the Great Devourer, the Chaos Bringer, the Planet Eater. His total goal is the reduction of all existence in every reality to nothing. He empowers his Heralds, gifting them with fleets of vehicles, vast armies, supernatural powers, and powerful insanity. Amongst his Heralds:
 * Galvatron, the reformatted Megatron, complete with a Cool Spaceship and an army of reanimated dead decepticons, transformed into super-warriors.
 * Megatronus Prime, one of the Original Thirteen, a warrior of Primus charged with overseeing all Entropy in the multiverse who Unicron corrupted into betraying his brothers. Henceforth, his name would forever be "The Fallen".
 * Scorponok, Humongous Mecha even by Humongous Mecha standards, and overseer of the Terrorcon hivemind.
 * Megatron, normally a vicious but rational warlord, loses his mind whenever exposed to the blood of Unicron, Dark Energon. Remarkably, Unicron doesn't want anything to do with this Megatron, perhaps due to how this has worked out for him in the past, and instead takes matters into his own hands.