Ever rub your hands together and notice that they warm up? That's friction, the force resisting the relative motion of solid surfaces, fluid layers, and/or material elements sliding against each other. Friction creates heat which can create a small flame if on a dry surface.
In fiction however, particularly animation, friction can cause one to burst into flames. This is usually Played for Laughs and is often caused by a character's own stupidity. In superhero fiction, characters with Super Strength might do this. One of the Required Secondary Powers of characters with Super Speed must be dedicated to avoid this. This trope may also be in effect when someone is using a Finger-Snap Lighter, or when Burning Rubber.
- In One Piece:
- This is how Sanji activates his Diable Jambe technique, by spinning in place at such a high speed the leg he's spinning on ignites.
- Also, this is supposedly how Hannyabal activates his Hannya Carnival, Blazing Hell Wheel attack.
- In Baka and Test: Summon the Beasts, Kouta is always trying to take pictures of the girls, always searching for a glorious Panty Shot. When he senses the opportunity to get a shot from Mizuki, he starts sliding all around her on the floor, trying to get the perfect angle. He sets himself on fire from the friction, then douses himself with his own blood from the Nosebleed that followed afterward.
- Invoked in Rozen Maiden whenever Micchan gets a bout of Cuteness Proximity dressing up Kanaria and rubs her cheeks against hers. Worse for Kanaria, since, being a doll, she's made of quite flammable material and while she never actually bursts into flames, it's clearly not comfortable for her.
- In Durarara!!: Mikado Ryugamine uses the internet so epically that his mouse catches on fire◊ from the friction.
- Fairy Tail: The Jiggle Butt Gang escape from the Zentopia dungeons by using this to light their asses on fire... It Makes Just As Much Sense In Context.
- Invoked in Battle Angel Alita. In her previous life, Alita had been sentenced to death by Atmospheric Exposure - meaning she was tossed out an airlock in a decaying orbit to burn up in reentry.
- In the finale of Kill la Kill, Senketsu performs a Heroic Sacrifice by shielding Ryuko from the heat of reentry using his own body and burns up in the process.
- Mega Man Megamix: Shadow Man kills Neptune by using him as a Human Shield against atmospheric reentry, letting his enemy get burned up by the friction whilst shielding himself. He tries to do it to Mercury too, but Mercury uses his melting powers to protect himself from the heat and escape.
- Discussed in Superman story arc The Plague of the Antibiotic Man. As battling an enemy in space, Superman comes up with the idea of encasing him in a prison fashioned from a meteorite. But he needs heat to melt the quartz into reflective glass, and there is no air-friction in space, so he uses his heat vision.
- Static villain Hotstreak possesses the ability to absorb the heat that is produced by his Super Speed and release it as powerful fire blasts.
- In Hellsister Trilogy, Supergirl's super-speed when she flies out of the planet causes the air to burst into flames around her. Being invulnerable, she ignores the effect.
The air friction formed a corona of fire around her as she streaked invisibly through the skies. She ignored it.
- In Here There Be Monsters, the air around Captain Marvel, Jr. flares up briefly when he rushes towards Mister Atom and Red Crusher at super-speed.
Junior sighed in relief, then set his jaw and flew downward like a meteor. His pace was so rapid that the aura of air friction was visible about him, briefly. He lanced downward towards the Menace of Metal, fists outstretched for a double hammer-blow.
- Apollo 13: When the crew is preparing to reenter Earth's atmosphere, the possibility of reentry friction incinerating them in the atmosphere becomes an Oh, Crap! moment.
Captain Jim Lovell: [Inspecting the jettisoned Service Module] "One whole side of the spacecraft is missing. Right by the high gain antenna, a whole panel is blown out. Right up...right up to our heat shield."
- Indiana Jones and the Temple of Doom: when the minecart's brake handle ends up busted, Indy tries to stop it by grinding the wheels with his feet before they hit the dead end. He barely makes it, but the friction leaves his shoes burning up and smoking.
- Pinocchio (2022, Disney): During the puppet show, Pinocchio dances so fast that his feet catch fire, causing Stromboli to douse him with a bucket of water. Later, when he and Geppetto and trapped inside Monstro, Pinocchio rubs his feet together to light the fire that will make the monster sneeze them out.
- As in real life, Kerbal Space Program applies reentry friction to a vessel entering atmosphere at orbital speeds. Heat shields are available for capsules and other craft, while spaceplane parts naturally resist heating. Proper flying technique is also required in order to gain the maximum protection from any shielding. Craft can and will overheat and explode catastrophically if improperly entered and/or insufficiently protected.
- In the final mission of Battletech, The Dragon's Spheroid Dropship is sabotaged on approach to the planet and enters a uncontrolled descent, cooking the insides and killing everyone aboard. While the ship was able to break enough that it avoids just bursting mid-air, the ensuing burning wreck quickly makes an uncontrolled landing since it no longer has any living crew.
- Adventures of Sonic the Hedgehog: In "The Mystery of the Missing Hi-tops", when Sonic's signature shoes are stolen, he tries running without them and burns his feet after a few seconds, explaining that they were specially designed to protect him from that.
- In an episode of The Powerpuff Girls (1998), Buttercup created a fireball by rubbing her hands together rapidly and threw it at a monster.
- In an episode of Family Guy, Peter drank Red Bull, giving him a rush of energy, and then milked a cow so rapidly, its udder burst into flames. In the same scene Chris, who also drank Red Bull, was seen running around screaming, pantsless and his groin ablaze.
- The Amazing World of Gumball gives us an example where Gumball is trying to start a fire through the friction & stick method. He ends up setting his hands on fire, and while he's running around screaming in pain, the wood he was trying to ignite catches on fire a few moments later. Cue the Rain.
- He also caught on fire from air friction when going down a hill too fast, while the friction with the ground tore the bike apart.
- In Dexter's Laboratory, when Dexter uses a Time Dilation device to go through his whole daily routine in 1 minute, he accidentally lights his homework on fire from the friction (and called it by the trope name at that). He needed to go through the same physics he has affected to counter this.
- In The Mask, once the Mask slows down a falling plane with his feet (as he stands in front of the aircraft's nose), he goes "Smoking"... as smoke is emerging from his shoes and he starts jumping in pain yelling "Hot, hot, hot!"
- In The Proud Family, "Poetic Justice", Oscar sets his hand on fire while trying to snap. A few seconds prior, PeaBo warned him about trying to snap too quickly, as that, combined with the "ashy-ness of his skin" could cause "spontaneous combustion".
- Similar, while in the middle of a Macho Disaster Expedition he remember how his mother always said his ankles were so ashy they could start a fire, so he tries it—and it works!
- On the Roger Rabbit Short "Roller Coaster Rabbit", Roger's feet catch fire while skidding down a roller coaster track.
- On the short-lived superhero spoof series The Ripping Friends, the main characters accidentally make Frictor, a malevolent friction elemental. He can cause friction burns strong enough to disintegrate anything (or anyone) in his way, though Frictor mainly uses his control over friction for dumb pranks.
- Steven Universe: One thing Peridot finds out about Jasper while trying to prove that the latter is inferior to Amethyst is that she melted the rock around her when she emerged.
- I Am Weasel: In "The Magnificent Motorbikini", Baboon forgets to put brakes on the titular vehicle, so he tries to stop it "the old-fashioned way" with his feet, which end up bursting into flame.
- Middlemost Post: When Angus slides down the pole of the crow's nest, the friction causes it to go on fire.
- One episode of Doug involves a school-wide athletic contest. Doug is pretty good at the rope climb, but loses his grip and slips down from the top, badly burning his hands. They're wrapped entirely in bandages, leaving him unable to do much else, only to get inspired by the phrase 'sitting around' to enter the sit-up contest. He wins, but then Ronald Weisenheimer congratulates him by shaking his hand.
- Ever wonder what those black tiles on the bottom of the Space Shuttle Orbiter were? Those are special heat-resistant ceramic tiles designed to protect the astronauts and vehicle. After all, this trope is played deadly straight when moving through Earth's atmosphere at orbital velocities. This protection requirement applies to every single reentry vehicle in the entire history of spaceflight, as temperatures may reach more than twice the ones of the Sun's surface. However, much of that temperature comes from atmospheric compression, not friction.
- A straighter example comes from classic fire-starting techniques, wherein two pieces of dry wood are dubbed together at high speed, usually using a string and brace, to raise heat enough that the wood combusts.