Demon Head

The sudden eruption of an enraged individual's head into that of a demonic monster many times its normal size, with bulging eyes, wagging tongue, pointed ears and teeth, and sometimes jets of steam or flame from its nostrils. Usually expected to cow the viewer into defeat or submission; usually doesn't work.

Compare with Scary Flashlight Face, Game Face, Burning with Anger and Looming Silhouette of Rage. Close relative of Nightmare Face.

Advertising

 * A seemingly innocent little girl playing with her dollie in an Eggo Waffles commercial, when her brother tried snatching one of her waffles. "L'EGGO MY EGGO!!!", indeed. Link to a video of that here. It proved to be too scary, so it was edited to this.

Anime and Manga

 * Soun Tendo, and occasionally his daughters, from Ranma ½. It became such a Running Gag, that at one point a nonplussed Akane calmed him down by literally pulling a cork from it and causing it to fly off like a deflated balloon.
 * Fujimura Taiga positively terrifies one of her students this way in the first episode of Fate/stay night, reducing the boy to a state of Blue with Shock.
 * Kiyomaro Takamine of Konjiki no Gash Bell (aka Kiyo of Zatch Bell) does this fairly often, even to having flames and heat-waves appear behind him.
 * More Nightmare Fuel, as well as more memorable instances of him here, here, and here.
 * Yukino from Kare Kano had an extended sequence of chasing down someone who angered her while in full Demon Head mode.
 * One Piece.
 * More specifically, Nami and Sanji have a tendency to do this a lot. Later on, it is actually weaponized by Emporio Ivankov.
 * The Chief from Dominion Tank Police was in a near-constant state of rage, complete with Cross-Popping Veins and bloodshot eyes; it didn't take a lot to push him over the edge into full-blown Demon Head mode.
 * An effect common in Pokémon anime.
 * "Leer" and "Scary Face", moves used in a battle, sometimes use this.
 * Jesse of Team Rocket sometimes does this when she gets angry at James and Meowth, e.g. in "One Trick Phony".
 * Misty occasionally does it when she gets mad at Ash.
 * You wouldn't expect Kagome to get to this point, but she does at least once. And Shippo tries to stand in for Sango.
 * Inuyasha himself does it at one point, too.
 * In GeGeGe no Kitaro, Kitaro's otherwise nice and quiet Catgirl friend Nekomusume would morph her face into a scary cat-monster when enraged or hungry for fish or mice. The version from Hakaba Kitaro is even worse, since it's less cartoony and more horror-like.
 * This happens a lot beginning in the late 200s to early 300s of Detective Conan when one character was yelling at another (usually in the more comedic episodes). Is usually Ran or Kogoro but could be anyone.
 * Hanaukyo Maid Tai
 * Episode 8. Happens to head security maid Konoe Tsurugi while Taro is trying to get Cynthia to go to sleep.
 * "La Verite''
 * Episode 1. Ikuyo Suzuki when she admits that she was lying.
 * Episode 5. Happens to Konoe again when Ryuuka asks to become one of the security maids protecting Taro. Konoe demands to know why they should hire Ryuuka, who is the leader of their enemies the Jihiyou family.
 * Episode 12. Two of Taro's personal maids get angry when the third keeps Taro to herself.
 * FLCL episode "Brittle Bullet". Haruko gets one when she's wearing an Elvis Presley costume and talking with Naota in his room.
 * In Sekirei, Miya is able to project one while maintaining a composed look. It still freaks out everyone that's looking at her at the time however.

Comic Books

 * The Animesque Gold Digger has a variation: Theodore Diggers' "Flaming Skull Bit".

Fanfic

 * In Fullmetal Lol,  grows a second head that tears out Ed's bowels whenever he  . And it is hilarious!

Film

 * Large Marge from Pee Wees Big Adventure was a source of much Nightmare Fuel because of this.
 * Similarly enough, the Librarian Ghost from Ghostbusters also did this. Interestingly enough, an earlier version of this puppet was rejected because it was too scary but then recycled and used in the vampire film Fright Night.
 * In the 1980s vampire film Fright Night, the third phase of vampiric transformation is just like this.
 * The dog PC in the film PAWS does this to scare off the main character's annoying little sister.
 * Yubaba's head is already huge, and when she gets spitting-fire and tentacle-hair mad it's damn scary.

Literature

 * Bes from The Kane Chronicles, whose trademark attack is to scare the shit out of his opponent by distorting his face hideously and screaming "BOO!" Not that he's that handsome when he's not making that face.

Mythology

 * More than a few Youkai and Obake are capable of doing this. Gaki, a type of life-stealing ghost created from humans who died of starvation (or while feeling avaricious or envious), are shapeshifters in general, but delight in suddenly assuming ghastly visages to startle and terrify. Ran, a Cute Monster Girl from Urusei Yatsura, is loosely based on the Gaki. According to traditional lore, Oni women normally look extremely beautiful, but can become terrifyingly ugly when angry or jealous.

Video Games

 * In Mortal Kombat 3, Kabal has a fatality where he removes his mask, exposing his horrifically scarred face. As per this trope, it appears to us with greatly increased size, glowing eyes, wagging tongue, and a rather chilling scream. This actually manages to scare his victims to death.

Web Comics

 * White Mage in this installment of 8-Bit Theater. (Scroll down a bit.)
 * Mobster Kingpin transforms into Demonhead Mobster Kingpin, who is predictably one of these. What's notable about this, however, is that once he transforms, he stays looking like that.

Western Animation

 * Ozu from Kappa Mikey tends to do this when angered. However, most of the characers work for him, so this generally does work, if only because he can fire all of them.
 * Exhibited several times by Starfire in the Animesque Teen Titans, usually when another girl was flirting with Robin, and once by Raven in silhouette.
 * Once, and only once by the titular character on the Asian-influenced Avatar: The Last Airbender, complete with waving arms, Blank White Eyes, Cross-Popping Veins, and face reddening. Due in part of the show's well-known characteristic of disdaining from over-the-top cartoony anime tropes in favor of utilizing the more cinematic style of anime, the effect overall left a bad taste in the mouths of viewers.
 * Courage the Cowardly Dog has a very creepy example of this in the episode "Courage in the Big Stinkin' City", with a girl playing the violin that Courage walks in on that changes into clay-mation.
 * Eustace also achieves a similar effect with a giant mask he pulls out of nowhere.
 * Numbuh 3 when you make her mad. Complete with flaming eyes.
 * Totally Spies!. Happens to Sam and Martin Mystery in the Crossover episode "Totally Mystery Much?"
 * The title character on Rocko's Modern Life, usually mild-mannered to a fault, gets really angry at Filburt and does this when threatening to do something NOT VERY NICE!!
 * APPLEJACK! YOU PINKIE PROMISED!!