- The "Jars" in Beetlesburg that criminals are put into for a very slow and public execution by starvation and sun exposure and then left to rot.
- The Slaver Wasps. Every thing revealed about them just makes them worse. The novels reveal they fuse to the nerves of their victims. And the reason they initially didn't work on Sparks? It's not because the Other couldn't make them like that, it just made a promise to the Knights of Jove.
- The horse....thing from early in the comic's run, seen through the next five pages.
- The fate of Passholdt, and its inhabitants.
- The Bad Future from Othar's Twitter adventures.
- Prince Aaronev's experiment when he's first introduced. The novel manages to take it Up to Eleven by mentioning twitching, and a small, strangled scream...
- Aaronev is all kinds of disturbing anyway. The man killed his daughter Anevka by putting her in the Summoning Engine, because he had a crush on Lucrezia.
- The various tools Agatha's forebears left in the medical lab she and Gil try to cure Tarvek in are all designed for horrifying uses, except the scream generator which was just for ambiance without it actually having to injure someone to make the noise, including replacing blood with molten brass and eight different types of electrocution.
- The fate of Hraggel's Point, as described by two of Gil's agents who had horrifying front row seats:Woger: Hraggel's Point. The whole town's been waspedand we were there. [...] We were supposed to sniff out [Herr Drumblebekk's] storehouses and trace his buyers. We tracked him to the second basement of a roadside inn. There was a hidden door in the floor, and when he went to open it it opened from the other side. I don't think he was expecting revenants. Yes, and these weren't just nice people mind-controlled by the Other... these were old style shamblers. They had masters. It was an invasion. Quiet. In the dead of night. They came up all over townthrough basements and tunnels. Once the town was infected they left the same way. Then everyone went back to sleep, like nothing had ever happened. It was really creepy.
- The Dreen. The first thing that both Tarvek and a Jäger General do upon seeing one is panic and run for it.
- Queen Albia is just plain freaky. Gil states that it's "literally unthinkable" for her subjects to disobey her, implying that she uses some kinda Mind Control or Hive Mind to control her people. The latter seems ruled out, but her absolute power over an (arguably) dying country is bizarre even in this universe as she's been alive for millenia as an immortal monarch. Her sparking out is also surprising. Judging by Voltaire's statements about her, you would assume she's relatively grounded and sane with control over her sparkiness. This isn't the case however. Whereas Voltaire and Klaus have very refined control of their "madness place", Albia gets almost completely consumed by it just as easily as a relatively green Agatha. Furthermore, she seems to want to make Agatha a permanent additional to her "garden" and seems to mean it literally, implying that she's been capturing and enslaving sparks for a very, very long time and forcing them to work for her. She also uses the Royal "We" when she speaks, but she is so insane that it makes you wonder if she doesn't literally have Multiple Personalities.
- When Tarvek starts figuring out who (or what) Higgs actually is, Higgs - who has been generally unflappable the whole time we've known him - laughs. And it's creepy as hell.
- The Other / Lucrezia's relationship with Agatha is all kinds of hideously messed up to begin with, but it's strongly hinted that she / it intentionally conceived Agatha solely to use in the Summoning Engine. And Agatha was conceived after Bill and Barry went missing, raising a few very squicky questions as to just how she was conceived...
- Albia's flashback to the deaths of her fellow queens, and more specifically who was responsible for it: Lucrezia. But she's clearly been through the wringer - she's much older looking, and has had several body parts replaced, including an eye and quite possibly her legs.
Nightmare Fuel / Girl Genius