Whenever a character becomes powerful enough, they will demonstrate Power Glows with a Battle Aura that can range anywhere from nightlight to supernova. Other characters aren't quite so flashy, instead of turning into a human candle, they become more akin to a human lampshade as light pours out of every orifice, as if they had a (potentially literal) inner fire.
Their eyes will glow, their mouth will light up as if they were about to breathe fire... or ice! Characters with a Throat Light can have it be related to just about any elemental power, or due to being a machine, ghost, or some other strangeness. As with most Psychoactive Powers, the lights will blaze strongly when angry, low when sad, and flicker when near death.
This can be really intimidating since it tends to be scathing hot/cold.
- Bleach. During "The New Captain Shūsuke Amagai" anime arc, several people have this while wielding Bakkōtō blades, including the assassin Hanza, Captain Amagai's father and Captain Amagai himself.
- In Rebuild of Evangelion, Shinji and Unit-01's awakened upgrade against Zeruel comes with this.
- Fairy Tail: Natsu when he has a ball of fire in his mouth.
- Naruto: The Tailed Beast V2 forms have bright-white glowing mouths, Glowing Eyes of Doom included.
- Finnegan from Witchblade (pictured above) when he's infused with the Elemental Powers of Ice... which somehow also causes blue Volcanic Veins thanks to Power Crystals.
- In The Order of the Stick prequel book Start of Darkness, Redcloak has light pouring from his eyes, throat and holy symbol the very first time he puts on the Crimson Mantle.
- In Batman Begins, when the city is hopped up on fear gas and they get a look at Batman, he's basically a bat-demon with a hellfire inner glow.
- Big Trouble in Little China. When in his ghost form, David Lo Pan can send a blinding light out of his mouth and eyes.
- The creepy alien angel guys from Knowing, whose creepiness is upped by their only apparent communication being opening their mouths and emitting a light and a wail.
- In The Lord of the Rings films, the Balrog has this. It is also glowing from various cracks in its skin, the implication being that it is simply a giant flame in demonic form cloaked by shadow.
- Devastator from Transformers: Revenge of the Fallen.
- The Matrix Revolutions. This happens briefly to Neo at the end as the machines channel their power through him to destroy the Agents Smith.
- The Wheel of Time has Ba'alzamon.
- Sorcerers in the Prince of Nothing books look like this whenever they start casting.
- In I, Jedi, when Corran opens himself fully to The Force for the first time, he finds it amazing, incredible, and says that he was completely filled with its power, which spilled and flowed from his eyes and mouth.
- In the Old Kingdom books by Garth Nix, Free Magic sorcerers flame from their mouths, eyes, fingernails, etc. as they cast, and get that way more and more, the more Free Magic they use, until they wind up as masses of flaming Free Magic. They appear to be fine with that.
- A Goa'uld torture device in Stargate SG-1 causes this effect on the victim.
- Jim Staal had a recurring character on... some Sketch Comedy show, possibly Big City Comedy, where he was the Anthropomorphic Personification of your refrigerator (and EVIL!), who had a light in his mouth whenever he spoke.
- Doctor Who: The Doctor does this when he regenerates (transforming from one actor to another).
- In Recettear: An Item Shop's Tale, this happens to Arma when she's being hacked into and taken over remotely or displaying a warning.
- In Dead Space 2, Isaac's recurring hallucination of Nicole has bright white light pouring out of her eyes and mouth.
- In Panzer Dragoon Zwei, the lizard-like Khouriats are killed by imperial decree if they develop one of these. Our hero Lundi decides to hide his when it grows wings as well.
- In a variation, this happens in Deus Ex: Human Revolution to the Final Boss when they overload and burn up from the inside.
- Deliberately invoked by Big Ears in Goblins to scare off a crowd of human civilians, by putting the Axe of Prissan through his head and aligning the glowing yellow orb on top of the magic weapon with his throat. Behold.
- Girl Genius: The "Fun-Sized Mobile Agony and Death Dispensors" (a.k.a. Devil Dogs) of Castle Heterodyne have this going. Not so much of a Power Glows example, though, since they're clanks.
- Avatar: The Last Airbender
- Aang while in the Avatar state.
- As well as Lord Ozai in the final episode, while Aang remove his firebending powers with energybending. Here, said Throat Lights are reaching Pillar of Light level.
- Puck, when he casts a spell, in Gargoyles.
- Raven from Teen Titans does this in the episodes "Spellbound" and "The End" parts 1 and 3.
- The gargoyle that offs Frollo at the end of The Hunchback of Notre Dame.
- Jack O Lanterns.
- Till Lindemann of Rammstein now sports a lit mouth as of the video for "Ich tu dir weh". It's removable, but he got a cheek piercing specifically for the purpose of wiring it.
- It is possible to get glow-in-the-dark braces.
- (Well, the ones on the face anyway... minus the ears and nostrils... okay, fine, just the eyes and mouth)
- Aren't they cats?