As this is a Nightmare Fuel page, spoilers will be left unmarked. You Have Been Warned.
“Some things, my boy... are better left unsaid.”
Danny Phantom is a show about ghosts, so of course Danny and us will be bound to experience all kinds of nightmares.
- The whole notion that Danny may be faced with Cold-Blooded Torture by his fanatical ghost hunter parents if they ever found out he was half ghost and the fact they voiced blatant hatred for Danny's ghost side fairly frequently. Hearing one's mother and father say they plan on tearing you apart molecule by molecule is easy nightmare fuel. Even Jazz (who secretly knows her brother is half-ghost) is disturbed by how their parents have been unwittingly scaring their own son and understands what he's feeling. She even calls them out on this in "Reality Trip".Jack: Whether it's air, land, or sea, I won't stop until we capture a ghost and tear it apart... molecule by molecule!
[Danny secretly cringes at those words]
Jazz: Danny, are you okay?
Danny: Who, me? I'm swell... [to himself] Every single molecule of me. - According to Butch Hartman, Danny's transition into a Half-Ghost was simply good fortune. If Sam or Tucker had gone into the ghost portal like Danny, they would have been killed.
- The "Masters of All Time" title card is possibly the most frightening with its portrayal of a feral, zombie-like Jack Fenton violently bursting from a clock and screaming murderously at the horrified Danny Phantom. While the episode itself does not have this actually happening, it definitely was a horror scenario just in one title sequence. Worse, all those hideous, pus-filled boils are everywhere, all over his body.
- "The Ultimate Enemy" has the creation of Dark Danny, where he looms over his trembling human counterpart, before he murders his human self. It's not shown what Dark Danny did to Danny before blowing up Vlad's mansion, but given his status as The Unfettered and Vlad's complete unwillingness to go into detail, it likely was not a pretty sight.Danny: What happened to my human self?
(Vlad cringes in horror as the scene pans down to his shadow and fades into a newly formed Dark Danny looming over his terrified human half... and Dark Danny unleashes his Nightmare Face, with red eyes and a slithering tongue, before he flies out of the exploding mansion with an Evil Laugh)
Vlad: Some things, my boy... are better left unsaid.- And just before that, Danny's ghost half claws Vlad's ghost form right out of him and then fuses with it. Dark Danny did some pretty disturbing stuff to his enemies.
- Dark Danny's creation. Vlad did not expect the Phantom half of Danny to violently react when he ripped it out (though given what he said about ripping out emotions, one could be said that all of Danny's emotional turmoil was left in Phantom). Then Phantom overshadows Plasmius and ends up absorbing him. Its utter scream of anguish pretty much makes the event less of a Face–Heel Turn and more of a Face–Monster Turn.
- The Bad Future outright showing Danny's family and friends being outright killed in a fiery explosion in one of Clockwork's flashbacks.
- The entirety of Danny's Rogues Gallery in the future, and all the awful stuff that was done to them: Ember's singing career when downhill after Dan severely damaged her vocal cords with his ghostly wail (leading to her becoming overweight after turning to Comfort Food as a coping method), and the Box Ghost is missing an eye and a hand, and he is definitely no longer the incompetent comic relief as we know him to be. Not to mention Damon, Valerie's father, who somehow lost an eye and one of his arms. However, the worst one has got to be poor Johnny 13 as he is inexplicably in a wheelchair. We never find out what Dark Danny did to him, Danny clearly doesn't want to know what his future self did to him, and given how much more hostile he, Kitty and Shadow are towards Danny than the other villains (no jokes, no Motive Rant, nothing), whatever Danny did to him was particularly horrifying.Johnny 13: Been waitin' a LONG time for this, punk.
- Jazz realizes that the Danny she's been speaking to is not her brother. Dan keeps an eerily calm demeanor while Jazz begins to lose it.
- Dark Danny turning around head first Exorcist-style, accompanied by a horrible cracking noise as his neck does things it clearly was not meant to do. His chilling line while doing this really makes him all the more menacing.Dark Danny: Nice try, Jazz. But me, my future, I'm inevitable.
- The scene where Dark Danny forces a Time Medallion inside Danny's body while the latter can do nothing but scream in pain.
- It’s extremely brief, but when told to name a second evil thing Danny has done, Clockwork shows the future, then concluding with a question that emphasizes his point. Just the sheer number he says illustrates the horrible things Dark Danny has done:Clockwork: How about two thousand?
- To really hammer the point down, at the beginning of the movie we get to see lots of ruins in what could perfectly be a post-nuclear disaster world in any other context... and since we are never shown if there are other ghost shield dome cities like Amity Park... well, it's not really hard to imagine THE ENTIRE PLANET is in ruins after 10 years of Dark Danny's rampage... and apparently, THE GHOST ZONE is just as destroyed.
- "Kindred Spirits". The darkest episode in the series after The Ultimate Enemy, naturally has tons of Nightmare Fuel as the above, if not more.
- Vlad planned to create a clone of Danny and then kill off the original. To make things worse, after Vlad's beloved stable clone was destroyed he had a huge Freak Out moment and was alarmingly close to murdering him and likely would have if not for a timely intervention by Danny's friends. Nightmare Fuel doesn't even begin to describe it.
- "...And then you will be obsolete."
- Also in that episode, when Vlad's clone son dies, Vlad himself faces Danielle with a terrifying face that screams pure violence and murder. Even after Danny first masters the Ghost Wail, Vlad got right back up again ready to rip them to shreds.
- Vlad trying to force Danny to "go-ghost" through the machine. Danny's in obvious pain and keeps stopping mid-transformation and yet Vlad still tries to force it until the machine explodes.
- And then there's Identity Crisis, the episode where Technus is accidentally released from the "Level 0" glitch. Danny attempts Form Duplication to fight him, resulting in nothing short of unadulterated Body Horror (least of which being mouths for eyes and eyeballs on ends of tongues).
- Vlad's motivation for becoming a villain (murder the protagonist's father so he can marry Maddie, his longtime crush and the protagonist's mother, and gain custody of her children and have the protagonist as his own son) is very, very, disturbing. This is repeatedly lampshaded in-series.
- The scene where Dani seemingly melts back into ectoplasm is both a Tear Jerker and nightmare fuel. Made even worse because it happens just after Danny does his last-ditch effort to save her.
- The scene at the end of "My Brother's Keeper" where Jazz uses the Fenton Peeler on Spectra. She literally removes layers of her youth until Spectra is an old lady. The fact that she gets older as her skin is being peeled off is seriously disturbing.
- Spectra herself is very unnerving because of how realistic her modus operandi is. Many teenagers have bad counselor experiences where they are blamed for their own problems or otherwise given irrelevant advice that overlooks their actual issues, and there's no way of knowing if you're paired with a bad one until you're in there. Coupled with the fact that Casper High is full of the spirits of deceased teenagers, imagine how much damage she had already inflicted before Danny dealt with her.
- When Freakshow turns himself into a ghost with the Reality Gauntlet, he really goes all out on making himself look like a nightmare creature.
- Freakshow's first appearance in "Control Freaks" had a scene where he has a Brainwashed and Crazy Danny with red eyes chase Sam onto a tightrope with a scythe, dressed up like the Grim Reaper. Danny's smile when he tries to kill Sam really doesn't help...
- The scene in which Poindexter first possessed Danny's body to be extremely disturbing, with the eerie green lighting, and Danny's contorting, spasmodic movements as Poindexter literally rips his spirit from his body.
- The scene in "Doctor's Disorders" in which Bertrand transforms is a major example of Body Horror: his skin glows green and begins to bubble as if it were boiling, while at the same time his head rotates gruesomely before his body expands and his scalp tears off, exposing his brain.
- Everything about Prince Aragon is very disturbing. He tries to kidnap a human teenager and force her to marry him, abused his sister for 1,600 years, while keeping a dictatorship where not even time could flow properly for just as long, and on top of it all his transformation into dragon form is terrifying.
- Danny screaming and writhing in pain from the Blood Blossoms in "Infinite Realms." For a ghost, just being near the flowers is like being under the Cruciatus Curse. And then Vlad shoves him into the circle so that he's surrounded by the stuff, making the pain ten times worse.
- Ladies and gentlemen, Pariah Dark, the King of All Ghosts: he's said to be so powerful that the only way he was stopped was when a group of ancient powerful ghosts banded together, and even then they just knocked him out long enough to put him in a sarcophagus that kept him from waking up. It's also implied that when Danny was fighting him, the Ghost King was merely toying with him. Then there's Ember's line.Ember: He's only been free for a day and he's already destroyed our homes!Danny: And that's without the ring.
- Undergrowth. That is one freaky plant. With a horrendous bird-like beak, and a self-regenerating plant body, this guy's definitely not gonna give you a break when it comes to the creep factor. Add that with the fact that he brainwashed Sam and turned the entire city into a hellish wasteland with everyone being brainwashed and acting zombie-like. The tip of the iceberg? He is voiced by the legendary Joker himself, Mark Hamill.
- Nocturne, the cartoon hybrid between Freddy Krueger, with his regeneration and dream manipulation, and the Black Doom, with his ruthlessness and power hunger. Creepy voice, universe colored body, and those beady red eyes. Plus he harnesses the dreams of his victims through special helmets.
- In "Parental Bonding", Sam's transformation into the dragon ghost is pretty creepy,
with her skin turning blue and scaly, teeth becoming sharp, and opening her eyes to reveal her pupils are now red slits.
