- The Terror Dopant has the ability to make reality bleed the stuff.
- Not only that, the scary aura earlier shown in episode 9 and 10 before being explained in episode 45 and 46. Terror Memory had the ability to amplify people's fear, especially on their human bodies' unconscious minds. This is the reason why even though the police and Shotaro knew that Ryuubei was the mastermind of Gaia Memories businesses or at least suspected, they cannot do anything about him. Because their bodies' unconscious minds are greatly frightened to approach the mansion. As shown in episode 45 and 46, Shotaro suffered mental breakdown from fear.
- Seen on the right, Terror's Terror Dragon. This creature itself even bite Accel Trial Form with its mouth, torturing him physically.
- The Twin Maximum is this trope as written. "Maximum Drive, Maximum Drive, Maximum Drive..." over and over again while Double writhes in pain, on fire, is just frightening. Philip was clearly against doing it for a good reason.
- The mantra returns during the final battle of "The B Carried on the Wind"...though the context is entirely different and makes it awesome.
- Utopia wiping the faces of Philip's friends in Episode 48.
- Daido Katsumi going Laughing Mad when all the psychics are killed. You can see the last vestiges of a good man dying, leaving only a vengeful Necro-Over.
- The way Isaka dies after Accel finally beats him in Trial form. His abuse of Gaiamemories leads to his Living Connector to grow violently out of control until it painfully consumes his entire body, leaving nothing behind. The similarity to an overdose death only makes it worse.
- The Utopia Dopant lights Kamen Rider Accel on fire in Episode 47. As if that wasn't scary enough, Ryu Terui screams in horror as he is burning to a crisp both in and out of his rider form.
- The Spider Dopant has the ability to implant spider bombs in people that make the people they love explode when they touch each other.
- The whole Virus Dopant storyline. Incredibly depressing considering how Sachi was treated by the man she loved and ungodly scary if you see that the dopant isn't her physical body, but a manifestation of her hatred towards him and the guys who ran her. Also, the way the dopant sounds and moves. It looks like something out of Resident Evil instead of the usual terrifying and sometimes goofy Monster of the Week
- Sonozaki Wakana. While in public, she was known as the gorgeous DJ Idol, her real personality is different, being rebellious and easily annoyed. In reality, when her little brother, Philip/Sonozaki Raito was gone. She suffered from being abused physically and mentally by her older sister, Saeko. Even though her encounter with Philip did changed her to be more cheerful and less violent, when Ryuubei takes the initiative to make her the successor of Museum, she becomes extremely frightening.
- In episode 41-42, when she gained the ability to enter Planetary Bookshelves from episode 39-40, the first thing she does is trying to take Philip away for Museum. Furthermore, Wakana even surpasses Philip in terms of Synchro Rate that she can transform into Dopant, while in that place, with Philip being helpless to do anything about it. Not to mention, the mad laugh that Wakana showed make it all creepier.
- Sonozaki Saeko. She is unpredictably ruthless to anyone. She even killed her husband, Kirihiko when he pleaded her to leave Museum with him. This happens because Ryuubei abused her physically when she was younger and did not loved her, prioritizing Wakana.
- The effect of using a Gaiamemory without a Living Connector as seen in the Farewell N episodes. It's not bad for a few times but eventually the memory burns a hole when it ejects after prolonged use. The makeup is disturbingly effective at making it seem like a memory sized chunk of flesh was just melted away. The fact that this disturbing imagery and needle-sharing drug allegory is being used on teenagers doesn't help matters.
- Specifically, since it is also made usable by non-authorised users, it ends up affecting the original user, Akane to the point of drug addiction even when her friends presumably use it quantitatively more than herself.
- It gets to the point where a normal Memory Break would actually kill the user. It took Nazca and Double to safely eject the Memory by aiming directly at the memory itself. Imagine if they were even slightly off.
Nightmare Fuel / Kamen Rider Double
Despite being a Lighter and Softer show and having a comedic tone most of the time, this show has its own fair share of Nightmare Fuel over the course of the series