Sometimes, Horrid Henry loves to push the boundaries of nightmare fuel. It's surprising how it's still a favourite among British kids.
- While Henry is still a massive Jerkass in the animated series, this is actually a case of Adaptational Nice Guy - believe it or not, he was much more horrid in the books than in the show, to the point of being an utter sociopath, often reaching Creepy Child levels.
- As a baby, he screamed almost constantly day and night, threw things around constantly, actually attempted to get rid of (read: kill) Peter when he was a toddler, and never, ever went to sleep.
- Unlike in the show where he sometimes shows love and respect to his parents and brother, it's implied that Henry genuinely hates his own family, up to the point where he isn't afraid to say it to their faces.
- Additionally, while Henry would never harm anyone who hadn't pissed him off (even if it often resulted in Disproportionate Retribution), in the books he remorselessly beats up other kids (especially Anxious Andrew and Weepy William) For the Evulz.
- He's so horrid in fact, that his parents try to pretend he isn't their son and even distance themselves from him when they go out in public.
- Henry dreams of taking over the world and ruling it with an iron fist. One thing he intends to do when being king is personally execute anyone who questions or disagrees with him.
- Apparently, Henry did something so horrid at Ralphs house, that it caused Ralphs parents to file a restraining order against Henry to prevent him from visiting again.
- Some of Henry's Imagine Spots can be rather disturbing (usually involving Henry transforming into an animal or fictional character, and eating/attacking Peter or other characters, but there are a couple of ones which are pretty terrifying:
- "Horrid Henry's Hike" has two:
- The first one happens when Henry realises that they're going to the countryside. He then theorises that giant man-eating chickens roam around it. While the whole scenario sounds [[Narm ridiculous]], the Imagine Spot that plays after Henry's protest is kind of disturbing, featuring him and his family running away from an army of chickens.
- The second one is even worse and even a minor Tear Jerker. It shows what could have happened if the chickens actually killed Henry. Henry's friends and family are walking up a dark hill carrying Henry's tomb while sobbing. The fact that the entire thing is represented by silhouettes and a nightmarish background is even worse.
- There's also "Horrid Henry's Sports Day", shortly after Henry fakes being injured, his mother tells him that she hopes he won't be operated on. The Imagine Spot shortly afterwards (pictured) shows Miss Battle-Axe about to cut him open with a chainsaw while he is strapped to a operating table, unable to do anything but scream.
- "Horrid Henry's Injection" has one when Henry reveals hes afraid of injections. He imagines himself winning a gold medal in a javelin competition, only for a nurse to come in and throw a giant syringe directly at Henry. In other words, considering the size of the needle, it's the equivalent of impalement.
- At the beginning of "Horrid Henry's Horrid Hamster", we are treated to what appears to be a fairly normal scene of Henry's class during a round of show-and-tell. Henry decides to present his prized possession, what appears to be a cardboard tomb with a mummy inside. As he switches it on, it nightmarish proclaims "I'M COMING TO GET YOU!" Apparently, this is enough to make the entire class, even Rude Ralph and Miss Battle-Axe, run out of the class screaming. After the imagine spot ends, it turns out that the mummy actually belonged to Peter.
- "Horrid Henry's Hike" has two:
- The climax of "Horrid Henry's Sleepover", in which during the middle of a night at New Nick's house, Henry has a brief nightmare where he is chased by some hounds across a never-ending corridor. Terrifying renditions of Nick's mother and father appear in coming out of the rooms. This then leads to Henry calling his parents to take him home, screaming while doing so.
- In "Horrid Henry and the Scary Scooter", Henry comes across Brainy Brian in the park while riding a scooter that he borrowed from Stuck-Up Steve. Brian just so happens to be reading a book about a cursed scooter, where its owner has to ride to until he dies. During the night, Henry hears the scooter supposedly calling to him from the back garden, leading Henry to believe that the legend is true.
- In the episode "Horrid Henry and the Alien Invasion", Henry is led to believe that Margaret and several other characters have been taken over by aliens because they are acting Out of Character towards him and singing a song about being lovely, which worries Henry to the point where he sets off the school's fire alarm to warn others of the invasion.
- "Horrid Henry and the Perfect Plant", almost the entirety of Henry's nightmare involves a plant which grows into a large Piranha Plant-type abomination. It starts eating the characters alive, with their bodies visible inside the plant. It is not implied if the characters are dead or not, effectively making the episode creepier.
- During "Horrid Henry Gets Rich Quick", after when Henry's mum finds out that Henry has sold his brother to Rude Ralph to earn some money, she takes her usual No Indoor Voice Up to Eleven by outright shrieking at him. The fact that it literally comes from nowhere is even worse.Henry: Well, I've sold everything I don't want, and I certainly don't want Peter; I sold him to Ralph!
Henry's mum: Well you go around to Ralph's right now and buy him back! [facepalms] You horrid boy!
Henry: But I don't want him back!
Henry's mum: HENRY, GO AND BUY YOUR BROTHER BACK RIGHT NOW!!!