[[quoteright:250:http://static.tvtropes.org/pmwiki/pub/images/message2.png]]
[[caption-width-right:250:Post-Its from nightmare land.]]

->'''Kryten:''' The poor devil must've scrawled it in his death throes, using a combination of his own blood and even his own intestines.\\
'''Rimmer:''' Who would do that?\\
'''Lister:''' Someone who badly needed a pen.
-->-- ''Series/RedDwarf'', "Psirens"

Maybe pen and paper weren't available. Maybe that just wouldn't be cool/creepy/dramatic/funny enough. This is a trope for writing with unusual equipment.

A particularly common (and gruesome) version is a victim of a murder or monster attack to use the last of their blood and strength to write a DyingClue. Also the blood will often be [[RustproofBlood immune to oxidization]], remaining bright red no matter how long. There may be {{Bloody Handprint}}s nearby as well. May cross with BloodStainedLetter as well.

See Also: DistressCall, RoomFullOfCrazy and DealWithTheDevil, all of which use or overlap with this trope to some extent. Sister trope to CondensationClue.

----
!!Examples:

[[foldercontrol]]

[[folder: Anime & Manga]]
* ''Manga/{{Bleach}}'' uses an instance that plays this trope every way ''simultaneously'' except for straight. Urahara tells Ichigo to leave his window open on the night that they leave for Soul Society, and on that night, he sends a balloon through the window, which splatters over Ichigo's wall. The liquid in the ball (which looks alarmingly like blood to Ichigo) drips down and forms a message. After the important bit of the message has been formed, it keeps on going to form a post-script: "Anyone who thinks this looks like the message of a dying man... has no sense of humor."
** Not even five minutes later, Ichigo runs into Chad and Orihime, who mutter about the fact that "apparently [they] have no sense of humor," leaving Ichigo to think "So they got that message too..."
* In ''Manga/DeathNote'' Light keeps a piece of death note paper and a pin for pricking his finger and writing in blood (couldn't fit a pen?) concealed in a secret compartment of his watch, so that he can kill someone quickly and discretely if necessary. He first uses it to kill the third Kira when [[YouHaveOutlivedYourUsefulness he becomes a liability rather than an asset]], while L is sitting right next to him. In the final episode after [[spoiler: getting his pen destroyed by Matsuda while trying to write down Near's name in the pages of the titular ArtifactOfDoom, Light continues writing with his own blood, which prompts Matsuda to blast the living snot out of him.]] This is actually a pretty severe "What the hell were you thinking" moment, as apparently at this point he had lost all self-control whatsoever and couldn't just calmly write down the name.
* Happens all the time to victims in ''Manga/DetectiveConan''.
* Parodied in one of the {{omake}} strips in the back of one of the ''Manga/FullmetalAlchemist'' volumes -- Roy reveals that he wants to make all the women in the military wear [[MemeticMutation tiny miniskirts]], but then also admits that he'd fire all of the men at the same time, which prompts them to shoot him. His last words are written in his blood on the floor next to him: "Miniski..."
** Lest we forget, Al's blood seal? The iron in the blood made it possible to bind his soul to the armor, so even if Ed ''could'' have found a ballpoint while flailing around in a sea of his own blood, it wouldn't have worked quite as well...
** Also the scene where, after losing his gloves and the runes inscribed on them, Roy carves his alchemical runes into his own skin.
* ''GhostInTheShell''. "Puppeteer'' is written in blood by the General in "Solid State Society" after he's forced to commit suicide by the hacker.
* In ''{{Hellsing}}'', a pair of vampiric serial killers write blasphemous messages on the walls of their victims' homes using the victims' own blood.
** During their first encounter with Alexander Anderson when Alucard gets [[MacheteMayhem pureed]], his sentient blood writes a message to Seras all by itself.
* In the ''Anime/LupinIIIRedJacket'' episode "[[Recap/LupinIIIS2E103 The Wolf Saw an Angel]]", Goemon, to prove his ImplausibleFencingPowers, cuts a series of steel beams being dropped on top of him into tiny pieces. The pieces of the beams land in exactly the right way to write out Goemon's name in kanji.
* In ''MacrossFrontier''[='s=] second movie ''The Wings of Goodbye'', [[spoiler: Sheryl Nome writes the lyrics to the eponymous song on her wall in her own blood]].
* While investigating [[NightOfTheLivingMooks the Mariage]] case in ''[[AllThereInTheManual StrikerS Sound Stage X]]'' of ''MagicalGirlLyricalNanoha'', one of the things found was an ancient Belka psalm painted in blood over an entire wall.
* Parodied by [[ADayInTheLimelight Sayo's chapter]] in ''Manga/MahouSenseiNegima''. Trying to calm down the panicking class after they mistook her for a [[OurGhostsAreDifferent malevolent ghost]], Sayo wrote "It's a misunderstanding" on a window. Unfotunately, since being a ghost, the only writing material she had was blood, and "It's a misunderstanding" in katakana is the same as "Death five times", all it did was make the class panic more.
* In chapter 53 of ''MiraiNikki'' [[spoiler: after the second Yuno is stabbed by the real Yuno, the other Yuno uses her last moments of life to write "Help Me" on the wall in her blood]].
* In ''Manga/{{Naruto}}'': [[spoiler: Jiraiya]] etches a dying message on [[spoiler:a toad]]'s back.
* In ''Anime/PrincessTutu'', Drosselmeyer is said to have written a story in his own blood [[spoiler:after the Book Men cut off his hands. Yes, it's implied he used the stumps.]]
* Parodied in ''Manga/SoulEater''. During an episode involving the entire cast taking a test, [[HighlyVisibleNinja Black*Star]] gets caught trying to steal the answers. The teacher beats the crap out of him and hangs him on the board as a warning. Later, when Soul is getting very desperate (having had his cheat sheets taken away), he sees Black*Star writing on the board in his own blood. Cue melodramatic inner monologue about how he must be trying to save his friend in dire straits- until Soul realizes it's [[ItsAllAboutMe an autograph]]. He is not amused. The audience is.
* While in ''Manga/SoulEaterNot'' [[spoiler: The final part of Episode 6 has the message say this "While you are sleeping. We still awake and keep watching".]] this is [[IncrediblyLamePun NOT]] for parody.
* In ''Anime/MobileSuitZetaGundam'' EnigmaticMinion Paptimus Scirocco signs a written pledge of his loyalty to BigBad Jamitov Hyman with his own blood. [[spoiler: Naturally, this means he eventually betrays Jamitov and usurps his position as leader of the Titans.]]
* In ''LightNovel/ACertainMagicalIndex'', Umidori Kuroyoru gets assaulted by Rensa and is left barely able to talk. She manages to warn Shiage about Rensa by writing in her own blood.
[[/folder]]

[[folder: Comic Books]]
* In "Calliope", ''ComicBook/TheSandman'' has a characteristically squicky example when Dream curses a writer with ideas. Lots of ideas. All at once. Making him try to scratch them out on the walls with his fingertips. [[AssholeVictim It's hard to feel sorry for him, though,]] considering [[spoiler: he kidnapped and imprisoned the titular muse of poetry just to get ideas for stories and get rich. He also rapes her from time to time, too.]]
* In an early ''Franchise/{{Batman}}'' comic, when Linda Page is being kidnapped, she insists the kidnappers give her a moment to fix her make-up (Hey! It was the 1940s. Criminals were more polite) and writes a note for Batman in lipstick on her vanity table.
* Played for laughs in ''{{Deadpool}}'', when the title AntiHero meets up with Alex "Agent X" Hayden, wins their scuffle, then proceeds to write messages using his entrails. And steals Hayden's pancreas ForTheLulz. Don't worry, [[GoodThingYouCanHeal Hayden can heal]].
* In a ''ComicBook/TheSimpsons'' comic, Lisa has to mark [[TheDitz Ralph Wiggum's]] homework:
-->"Did he write this in crayon?"
-->"He used a crayon until he ate it. Then he used mustard. For the last two questions he-"
-->"Nevermind. [[YouDoNOTWantToKnow I don't want to know]]."
* Done literally in the ''SquadronSupreme'' trade paperback; the first edition was printed with the cremated ashes of writer Mark Gruenwald mixed in the ink.
* A writer character in ''ShadeTheChangingMan'' has the ability to extract the abilities and characteristics of real people for use in his stories. When he bases one character on Lenny he takes away her unique and caustic wit, and when she realizes this she freaks out by scribbling "It just isn't funny anymore" in lipstick on the bathroom mirror before [[spoiler: trying to kill herself]].
* In ''ComicBook/OneHundredBullets'', a woman writes "He's going to kill me" in her lipstick on the bathroom mirror in Wylie's gas station, referring to her husband, who she's with. (Wylie acknowledges that he received the message when he compliments the woman on her shade of lipstick.)
* In one ''Magazine/{{MAD}}'' "A Mad Look At..." a dead man, having been fatally shot, used his blood to not only identify the killer (his partner), and also [[HeKnowsTooMuch his motive for doing so]]. This is especially surprising in that "A Mad Look At..." typically has no dialogue, only {{RebusBubble}}s and small signs.
* In a {{Superman}} one-shot, ''LexLuthor: The Unauthorized Biography'', Sands, a hack reporter who was writing [[ExactlyWhatItSaysOnTheTin Luthor's unauthorized biography]] was found murdered, the letter "C" written in his blood. As it was known that Sands had heated words with Clark Kent earlier, Kent was initially a suspect in Sands' murder, until a lawyer hired by Lex Luthor provided evidence that the victim couldn't have written the "C" because the angle it was written in was wrong. [[spoiler: At the end of the story, it was revealed(but not to the police) that [[EvilPlan Luthor had Sands killed and Kent framed, and then sent his lawyer to prove Kent's innocence]]. The lawyer then told Kent that Kent now owed Lex Luthor a favor.]]
[[/folder]]

[[folder: Fan Fic]]
* {{Lampshaded}} in the ''Manga/DeathNote'' fic ''FanFic/LowLight'':
-->'''L''': You can be incredibly creepy when you want to be.
-->'''Light''': Creepy?
-->'''L''': You question whether writing a message to someone in another's blood upon the floor is creepy?
-->'''Light''': I suppose you have a point there L, but it was the only writing material I knew the man would have readily available.
* Appears in Kingdom Hearts story [[http://www.fanfiction.net/s/5230474/1/Ill_bNever_b_Be_bEnough_b I'll Never Be Enough]] when Cenchaze writes his goodbye (and several other notes) in his own blood.
* Happens in the ''Fanfic/PonyPOVSeries'' [[BadFuture Dark World Series]]. While sending the murder of blackbirds that have been tormenting Derpy for the last thousand years to Ponythulhu's realm, Twilight takes time to write a letter with a blackbird pie recipe to the big guy because [[DidWeJustHaveTeaWithCthulhu Ponythulhu is actually a pretty nice guy]] and they want to be respective to him. Since she ''literally' doesn't have a pen, she pulls one of Spike's (now a giant adult dragon's) scales off and writes the letter in her blood. Justified in this case because finding a pen in time wouldn't be possible, and Twilight has CompleteImmortality and will just regenerate the lost blood.
[[/folder]]

[[folder:Films -- Animated]]
* ''WesternAnimation/{{Megamind}}'' has the titular character writing notes about his plan with a jelly donut.
* In ''WesternAnimation/TheIncredibles'', Gazerbeam used his laser vision to zap the word "KRONOS" into the wall of the cave he died in. Mr. Incredible finds it and eventually figures out that it's [[spoiler: the password to the latest project that Syndrome's been planning]].
* In ''WesternAnimation/BatmanBeyondReturnOfTheJoker'', a scene involves Bruce Wayne being found after an attack by the joker with "Ha! Ha! Ha!" written on the ground in red. It was changed to purple in the censored version to avoid looking like this trope.
[[/folder]]

[[folder:Films -- Live-Action]]
* Done by a dying man in ''Film/{{Constantine}}'', using a corkscrew as a pen and his own hand as paper.
* ''Film/WhoFramedRogerRabbit'' had two versions of this trope using the same sheet of paper! Roger's alibi for murder is that he was writing a letter to his wife with her lipstick on a "nice, clean, sheet of paper" which [[spoiler: turns out to be Marvin Acme's will, (the MacGuffin of the movie,) which has been written in ACME's Disappearing-Reappearing Ink.]]
* ''Film/TheUntouchables'': After [[spoiler: murdering Oscar Wallace and George the Bookkeeper in an elevator]], Frank Nitti uses [[spoiler: their blood]] to write the word "TOUCHABLE" on the wall.
* In ''Film/{{Quills}}'', the Marquis De Sade has his writing equipment confiscated and resorts to writing on his clothes, first using red wine and eventually bodily fluids.
* Averted in ''Film/{{Memento}}'' where the main character is stuck without a pen and desperately needs to write something, but ''doesn't'' manage to find a workable substitute. However he does tattoo himself as a way to remind himself of important information.
* Dr. Lizardo in ''Film/TheAdventuresOfBuckarooBanzaiAcrossThe8thDimension'' made a RoomFullOfCrazy by writing on the walls with ... chalk? Charcoal?
* Miss Froy in ''Film/TheLadyVanishes'' writes her name with condensation on the train window. When the heroine sees it again, it confirms to her that she's not crazy and something is amiss.
* In ''Film/{{Transformers}}'': Revenge of the Fallen, Sam starts having a mental breakdown in the middle of a frat party, and in order to get the symbols out of his mind, he starts drawing them on the table... with cake frosting.
* ''Film/JourneyToTheCenterOfTheEarth'' (1959). Explorer Andre Sarcassan leaves a message in blood on a plumb bob which -- encased in a lump of volcanic rock -- is retrieved centuries later by the protagonists, sending them on their journey into the HollowEarth.
* In ''Film/{{Charade}}'', a knot of conspirators are dying off one by one - [[spoiler: James Coburn's character is found with hands and feet bound to furniture legs and a plastic bag over his head]] - he used his finger to spell his killer's name in the carpet.
* In ''Film/{{Sisters}},'' the dying man crawls to an open window, and writes "HELP" with his bloody finger, one of the few practical examples of writing something in blood in all of filmdom, as someone does actually see him do it-- and there was a possibility at that point that he might not have died if he'd gotten the attention of someone a little more quick-thinking. By the time she figures out which apartment he's in, someone has managed to finish him off, hide the body, and clean up.
* PlayedForLaughs in the Hong Kong comedy ''Justice My Foot.'' Creator/StephenChow plays the protagonist Sung Sai Kit, a [[GuileHero cunning lawyer]] who wins via clever ploys and his wits (seriously, he wouldn't be out of place in the ''VisualNovel/AceAttorney'' universe). [[spoiler: Jailed towards the end of the movie, he has to get the attention of the high magistrate, and as he is in prison, has no access to brush and ink. He writes a message in blood on a fan... by biting the finger of the man who presents the fan to him as evidence of innocence in a previous incident, and using said finger as a brush instead of biting himself, as is expected by Asian sensibilities.]]
* ''Welcome to the Punch'' (2013). A female detective has a habit of writing notes on her hand, instead of taking out a notebook. [[spoiler:When the protagonist finds her dead at the morgue, the final vital clue is there for him to act on.]]
* As Detective [=McCarthy=] searches for Jenke in the opening flashback of ''Film/TheHorrorShow'', he comes across of one cop's severed head placed on a table with "blue platter special" written in blood on a wall next to it.
* ''Film/{{Outpost}}''. After [[DwindlingParty the first two mercenaries die]], Prior heads out of the bunker with a bed sheet marked "5" to tell the undead Nazis just how many are left, then tells them to "[[BadassBoast bring it on]]". When they kill Mac, the Nazis then respond in kind by tying his corpse to the post, with a "4" carved into his chest.
* A variation in Abel Gance's ''Napoleon''. Marceau does have a pen and paper but there is no ink, so he pricks his wrist and signs the army register with his blood.
* Another variation in ''The Killing Room'' (2009). Several people are locked in a white-painted room and forced to take part in a lethal MindControl experiment. One of them finds what appears to be a message from the previous occupants scratched into the wall. The words have been painted over, so they take the blood from a member of their group who has already been killed and smear it on the walls to make out the words. A cut later there's blood smears all around the room, [[NightmareFuel showing they're just the latest of many victims]]. Turns out the words have been put there deliberately by the researchers, so having to use blood to see them is likely a deliberate MindScrew.
[[/folder]]

[[folder: Literature]]
* ''TheDaVinciCode'' does this in the first chapter. Possibly includes a ShoutOut to ''Monty Python and the Holy Grail'':
--> '''Sophie:''' Why would a dying man bother to write out "P.S.", Mr. Langdon?
** Though he only used the blood to make the police use ultraviolet lamps. He did have and use a pen, but one with invisible ink (except in UV).
* In ''Film/ChittyChittyBangBang'' the children are prisoners of the mob, and are forced to write a message for help by pricking pinholes into a large-denomination franc bill.
* In one of the ''Literature/{{Lovejoy}}'' novels, Lovejoy writes a note using his own urine as invisible ink.
* In the Creator/RobertAHeinlein short story ''GoldfishBowl'' the protagonist is captured by aliens. He repeatedly scratches himself to make scars and form a message on his skin.
* This happens repeatedly in ''Literature/{{Discworld}}'':
** In ''Discworld/MovingPictures'', CMOT Dibbler tries to write down an idea for a film that came to him in a dream on his bedsheets; he runs out of bedsheet and starts writing on a wall, which he then pays a troll to carry around for him.
** The same thing happens in ''Discworld/ThiefOfTime'', when Jeremy gets the idea for the [[{{Macguffin}} Glass Clock]] in a dream and ends up writing the specifications for it all over his bedsheets and part of the wall.
** In ''Discworld/MenAtArms'', Detritus, a troll, is trapped in a freezer, and the cold temperature brings his brain to peak efficiency. Unfortunately, this also means he's probably going to freeze to death, so as he gets smarter (and closer to death), he starts writing a mathematical grand unified theory of everything in the frost on the walls. He gets up to the = sign when he freezes up completely; when he's rescued, the heat from opening the door causes the rest of the equation to melt away.
** In ''Discworld/{{Thud}}'', a dying dwarf miner uses the last of his strength to scrawl a cursed mine symbol onto the door he was trapped behind.
* OlderThanPrint: Writing an important letter in blood (complete with dramatic biting of the finger) is a great way to get across that your message is Top Priority. (That might be why in China, the Emperor gets to use red ink.) One such message is written in ''Literature/RomanceOfTheThreeKingdoms'' in an attempt to get rid of Cao Cao; the note is found, and all of the signatories end up being fugitives of the government.
* A mention of this trope is made in ''Literature/TheBelgariad'': When the party finds themselves in such a situation, Polgara has a quill, ink, parchment, etc, and explains that on a [[ReallySevenHundredYearsOld past occasion]], she found herself needing to leave a note ''without'' the necessary implements, and ended up using her own blood to write the message. Following the event, she took steps to make sure it wouldn't happen again.
** This also creates some FridgeLogic as this is a series where they can create anything at will. So if they needed a pen/paper/ink, they can just create them out of thin air.
*** It is also a series where their enemies can hear them create things at will, and thus there are times when such techniques are not just inconvenient, they are downright dangerous.
** Subverted in the ''Malloreon'' where Belgarath curses whoever was stupid enough to write an important prophecy on human skin: The ink didn't "hold" and Belgarath was forced to go ''yet'' elsewhere to try and find that prophecy.
* Subverted in the Creator/AgathaChristie novel ''DeathOnTheNile'': a murdered woman uses her own blood to trace a letter on the wall, presumably the first of her assassin's name. It later turns out that [[spoiler: the killer wrote the letter. In a double-twist on this trope, it was written to implicate one of the people actually directly involved in the murder, in an attempt to make it look like another party was trying to frame her.]]
* Creator/MarkTwain's ''TheAdventuresOfTomSawyer''. Tom and Huck Finn swear an oath to not talk about seeing Injun Joe murder Dr. Robinson. They write the oath on a shingle and sign it in their own blood.
* Played with in ''Literature/HarryPotterAndTheOrderOfThePhoenix''. Harry is forced to do lines as punishment for telling the truth about Voldemort and is given a pen with no ink. He starts writing, and the message comes out carved across the back of his hand. Played straight in ''[[Literature/HarryPotterAndTheChamberOfSecrets The Chamber Of Secrets]]''. [[spoiler: Ginny]] writes threatening messages in blood while brainwashed.
* In ''Mr. Bean's Scrapbook'', the in-universe tie-in for the film ''Film/{{Bean}}'', a running gag is that Mr Bean keeps having to switch to new ways of writing: first his typewriter breaks, then his "borrowed" word processor is taken back, then he resorts to using a child's printing kit which takes three hours to lay a (mostly backward) sentence, then a pen which runs out, a crayon and a pencil which break, and finally he ends up using his own blood to refill the pen.
* In ''Something Wicked'', a murder mystery based on ''Theatre/{{Macbeth}}'', Duncan is found dead with "Malcolm" written on the wall of his tent in blood, which seems to implicate his son... except the hero realizes that everyone, including Duncan, called his son Mal, and it's unlikely that a dying man would have bothered with the extra letters. It turns out to be a frame-up by the real killer.
* The Creator/NeilGaiman-authored Literature/SherlockHolmes[=/=]CthulhuMythos pastiche ''Literature/AStudyInEmerald'' has the two main detectives ([[spoiler: ''not'' Watson and Holmes]]) called to the murder of the nephew of Queen Victoria (actually one of the Great Old Ones). They find the word "Rache" written on the wall in blood. ''Green'' blood.
* In ''A Study in Scarlet'', Literature/SherlockHolmes finds 'Rache' written on the wall in blood. Lestrade wrongly concludes that a woman called Rachel is involved, and the victim died before finishing the name. Rache is German for revenge, and the murderer [[spoiler: who was American intended for the police to believe it was committed by a German. Holmes wasn't fooled when he noticed that too much effort went into making the handwriting look German. The blood is also not from the victim, but from the murderer whose nose bled because of the excitement.]]
* In the ElleryQueen novel ''The Scarlet Letters'', a dying man uses his own blood to write XY on a wall in an extremely cryptic DyingClue.
* And in the unrelated ''TabletopGame/VampireTheMasquerade'' story "Scarlet Letters," a girl cuts her own throat and uses the runoff to start writing ''poetry'' on the wall while she's bleeding to death.
* The Creator/BanjoPaterson poem "Clancy of the Overflow" contains this line (known to all Australian school children):
-->"And an answer came directed in a writing unexpected\\
(And I think the same was written with a thumb-nail dipped in tar)"
* Creator/StephenKing's ''Literature/{{IT}}'' has Stanley Uris, one of the protagonists, commit suicide in his bathtub because [[spoiler: he doesn't want to go back to Derry to face It again]]. When his wife finds him, she finds that he's written the single word "IT" on the bathroom wall in his own blood.
* In Creator/LarryNiven's ''[[Literature/KnownSpace The Patchwork Girl]]'' the victim leaves "NAKF" written in his own blood on the rocks of the lunar surface. [[spoiler: He was trying to write "NAKED" indicating that his killer was naked: i.e. not wearing a space suit, which is quite a trick out on the surface of the moon.]]
* In ''JonathanStrangeAndMrNorrell'' Childermass briefly attempts to copy [[spoiler: the Book of the Raven King, which had been written as blue discoloration on a man's skin]], onto his own flesh. He quickly gives up for some of the many, many reasons no one should ever even try to copy out something in a language they don't know onto their skin, with a penknife, all alone in a cold and isolated area, [[spoiler: when the book covered the man's entire body except for groin, face and hands, and for all he knows size and placement of the marks is vital.]]
* In ''Literature/NewMoan'' (a parody of the ''Literature/{{Twilight}}'' saga), this trope is played with. Teddy (the Edward {{Expy}}) gives Heffa (the Bella {{Expy}}) a note, written in some red substance. Heffa asks if it's blood, to which Teddy replies that blood is useless as ink since it clots too quickly, and it's just normal red ink.
* ''[[FelixCastor Thicker Than Water]]'' has Felix called out to a crime scene where his name is written in the blood. [[LampshadeHanging Lampshaded]] in narration: "The words '[[WesternAnimation/TheSimpsons Use a pen, Sideshow Bob]]' flitted incongruously through my brain."
* In ''ASongOfIceAndFire'' people who join the [[PrivateMilitaryContractors Second Sons]] traditionally sign in blood. They abandoned this tradition some time ago and started using red ink instead, because blood makes terrible ink. [[spoiler: When he joins the company, Tyrion mixes some of his blood into the ink he signs with.]]
** Stannis Baratheon uses his own blood to sign an accord with the Iron Bank of Braavos, because his ink has frozen.
* In Brazilian book ''A Droga da ObediÍncia'', one of the protagonists is captured inside the school. Just before being dragged out of the place, he asks his kidnapper to go to the bathroom, and uses the contents of a toilet to write a Morse code message to his friends.
* The Literature/EighthDoctorAdventures gives us the two-novel story ''Interference'', wherein [[spoiler: the Doctor]] winds up using his own blood to [[RoomFullOfCrazy cover the floor of his cell with arcane mathematical formulae]].
* In ''Literature/ABrothersPrice'' Jerin was burning a letter when people came through secret passages and abducted him. He struggled for long enough to be able to write one three-letter word in soot before they hauled him away, the name of the one he thought responsible. Many characters in that world are illiterate, and they didn't have time to clean up as his bodyguards were trying to break through his locked door.
* In ''TheLaundrySeries'' the Official Secrets Act and other non-disclosure agreements have to be signed in blood -- a sterile lancet or disposable needle and Sharps container are thoughtfully provided.
* In ''Literature/{{Hours}}'', the ninth class to inherit the secret gymnasium discovered that the 8th class had stolen all the markers out of the gym. Since the scanner at the door prevents anybody from bringing foreign objects ''into'' the gym, the ninth class had to write the rules to their game using blood. The tenth class avoids this by writing their rules using the poison ink secreted from a plant Alexis grows.
[[/folder]]

[[folder: Live Action TV]]
* Happens from time to time on ''Series/{{NCIS}}'', generally of the giving-a-clue-as-to-the-murderer variety. Except for the time it was a call for help. Unintentionally aimed directly at a NCIS investigator... Which also ID'd the person making that particular call for help.
* From a [[http://www.youtube.com/watch?v=m1NdFeJHnmU deleted scene]] of ''Series/BeingHuman'':
-->The two see GetOut written in red on the wall.
-->'''Mitchell''': Oh, shit!
-->'''George''': Shit! What is it, blood?
-->'''Mitchell''': Paint, and it's still wet. Tch. Blood. You ever try writing anything in blood? It's totally impractical.
* From ''{{Becker}}'': "Look, writing your name in the snow with your pee is good drunken fun when your name is something like Joe Smith. But, when your name is Stanislav Kasacinski and it's ten below out, you're just frostbite waiting to happen."
* ''Series/RedDwarf'' has a dying RedShirt scrawl a warning using blood and intestines. The Cat wonders why he went to the trouble of using his kidney as a full stop. Rimmer notes that it probably just "plopped out" on its own. In ''Better Than Life'' (the book), the crew get stuck in a virtual reality game and the only way to communicate with them is by carving messages into their arms.
* There's an episode of ''Series/{{Friends}}'' where Phoebe writes a phone message on the back of Chandler's neck.
-->"Get the woman a pad! A PAD!"
* [[TopGear Jeremy Clarkson]] declared that the Dodge Viper was a car "so sophisticated, it could write its own name." He then proceeded to write the word 'Viper' on the test track, using skidmarks.
* ''Series/{{Angel}}'' used this trope a lot for ghosts. In season one, a malevolent spirit wrote messages on the walls of Cordelia's apartment. In season five it was the messages in the condensation of Fred's shower door.
** Legal documents at Wolfram & Hart are shown being signed in blood.
* ''Series/JonathanCreek'' used the contract-signed-in-blood version in the season three episode "The Curious Tale of Mr Spearfish".
* A classic ''Series/SesameStreet'' sketch has Ernie writing a shopping list with chocolate pudding, because he couldn't find a pen, a pencil, a crayon or a typewriter.
-->'''Bert:''' He's improving. Last time he used spaghetti sauce.
* ''{{Blackadder}}'': "I'm sending off some party invitations and to make them look particularly tough, I wish to write them in blood. [[BumblingSidekick Your blood, to be precise]]."
* Seen in the ''Series/{{Torchwood}}'' episode, "Captain Jack Harkness." Tosh and Jack are stuck in the past, and need to send a message that will last the next 60 years and be found by the other members of their squad. Tosh doesn't have a pen, so she cuts her hand open on a rusty can and writes in her own blood. Also seen in "They Keep Killing Suzie." The word "Torchwood" is written in blood on a white wall on a crime scene.
* ''Series/DoctorWho'' is a fan of this trope, as well. River Song, in particular, once used a blowtorch to write "Hello Sweetie" in high Gallifreyan on a starship's black box to be found by the Doctor 12,000 years later. She also carved a message on the diamond cliffs of planet One, making it the oldest written words in the history of the universe, because the Doctor wouldn't answer his phone.
** Amy and Rory use a car to make a crop circle reading "DOCTOR" in order to get his attention in "Let's Kill Hitler".
** A variation of this trope appears in "The Invasion" starring Patrick Troughton as the Doctor. One of the characters in the story has the habit of scribbling notes on her apartment walls using the irrefutable logic, "You can lose a piece of paper, but you can't lose a wall."
** "The Day of the Doctor". The War Doctor blasts his [[ArcWords NO MORE]] message into a wall using a laser gun he borrows from a Gallifreyan soldier.
* The opening episode of Season 4 of ''Series/TheXFiles'' had [[spoiler: X, Mulder's then-informant]] writing a message in blood on Mulder's doorstep, having been shot trying to bring information.
* In ''Series/BuffyTheVampireSlayer'', after Angelus kills [[spoiler: Jenny's uncle]] the day he had sex with Buffy, he writes a message to Buffy on the wall -- "Was It Good For You Too?" in the victim's blood.
** In ''Conversations With Dead People'' Dawn sees what appears to be her mother, and the incredibly creepy words 'Mother's milk is red today' appear on the wall. Unlike in the first example, this blood was red not brown. Because RustproofBlood was averted in [[http://tvtropes.org/pmwiki/pmwiki.php/Recap/BuffyTheVampireSlayerS2E14Innocence the first instance]], it can be assumed that this blood is actually meant to be fresh.
* Played for laughs in [[http://www.youtube.com/watch?v=yt25hZDZzEo this]] comedy sketch by Jinnai Tomonori.
* John Crichton in ''Series/{{Farscape}}'' lured Scorpius into a trap by using the complex-looking equations for wormhole navigation written in blood on the floor of the holding cell. [[SpecialEffectsFailure It was rather obviously ketchup.]]
* In the ''Series/{{Charmed}}'' episode "The Power of Three Blondes," the Halliwell Sisters are replaced by three [[BlondesAreEvil evil blonde impostors]] who are all [[BrainlessBeauty Brainless Beauties.]] While impersonating Phoebe, Mitzy Stillman gives Phoebe's newspaper-editor a report written in eyeliner (she was intentionally trying to get Phoebe in trouble with her boss). When explaining why it's written in eyeliner, Mitzy claims that, you guessed it, "I couldn't find a pen."
* In an episode of ''Series/{{Bones}}'', Bones was being framed for the murder of a friend incarcerated in a mental hospital. It eventually turned out that the victim had left a long and complex clue by writing in his own saliva which only showed up under a blacklight when Hodgins and Cam search his room looking for a clue in a triangle.
* ''TheSarahConnorChronicles'' had one of these which was even more absurd than the usual examples of this trope. In the beginning of the second season, a guy makes the jump from the future to the past but is shot when he does so. He needs to get his message to Connors, so what does he do? He breaks into their basement and scrawls a confusing and incoherent message on the wall with his own blood then visits upstairs, whispers something cryptic then dies. He sure failed at that mission.
* In the pilot episode (Days Gone By) of ''Series/TheWalkingDead'', Rick comes across an abandoned farmhouse where the two former inhabitants had scrawled "God Forgive Us" in blood on the wall before committing suicide.
** Used to oddly-heartwarming effect in Season 4. After [[spoiler:the prison is overrun]] and everyone is separated, Maggie leaves notes, scrawled on walls in the blood of walkers, to tell Glenn where she's going. The smile on his face when he finds it is priceless.
* A sketch on ''[[Series/BlueCollarComedy Blue Collar TV]]'' had Larry the Cable Guy calling Information for the number to 911 and, not having a pen, bit the tip off a strawberry to write it on the wall.
* ''Series/StarskyAndHutch'' has two opposed examples. In the episode "Bloodbath", Starsky is kidnapped by a murderous cult, who leave his name scrawled in blood on a mirror for his partner to find. In "The Plague", Hutch is in an isolation room with a fatal disease; before Starsky leaves to go look for a cure, he uses a borrowed lipstick to write his name on the observation window where Hutch can be reassured by it.
* ''Series/{{Luther}}''. A Satanist killer abducts a woman from her home and leaves the corridor leading from the front door covered in words written in blood such as DO NOT FEAR THE ABYSS, I AM THE ABYSS. Likely a deliberate use of the trope to add to his reputation and creep people out. Also a deliberate taunt to the police, as the blood had been kept frozen from a murder the police had been unable to pin on him years before.
* On ''[[FlashForward2009 FlashForward]]'', when [[spoiler: Lloyd Simcoe is kidnapped by Flosso]], he tries to write a note like this, using his blood as ink and a flyer for paper. [[spoiler: It's blown away though, and only found after he's rescued.]]
* In ''TwoPointFourChildren'' Ben witnesses a hit-and-run and rushes into the kitchen shouting the car's registration number (license plate) over and over so he won't forget it. Not having a pen, Bill writes the number on a cucumber with a tube of mustard.
* ''{{CSI NY}}'' did a variant where the victim didn't write the message-it was written by the killer in an attempt to implicate someone else.
* An episode of the Live-action ''LargoWinch'' shows a woman joining a group of villains, and signing her name with her own blood.
* The angel-banishing sigil on ''Series/{{Supernatural}}'' does not count, as it has to be drawn in blood or it doesn't work. However, there was an episode where Sam drew a devil's trap (which does ExactlyWhatItSaysOnTheTin) in his own blood for lack of any other medium.
* An episode of ''Series/{{Castle}}'' starts out with a murder victim who wrote "LIE" on the ground with her blood as she lay dying. [[spoiler: Turns out they were looking at it [[DyingClue upside-down]]: it was actually the number "317".]]
** Another episode had "Murdere" written in the victim's blood on a mirror. For a while Castle muses that it implies the killer is foreign "Murdere, he's French! Murdero, he's Spanish!" (The final letter wasn't very clear and could have been E or O.) [[spoiler: It was written by one of the two (yes, two separate) killers in an attempt to frame an extreme animal rights group that had been protesting the victim's company for animal testing.]]
* Premier episode of BBC's ''Series/{{Sherlock}}'', where a woman clawed a vital clue into the floorboards.
* ''Series/{{The Mentalist}}'' has the main bad guy, Red John, write a symbol on the wall with his victim's blood, which drove the main character to work with the police to try to catch Red John.
* An arc of ''EarthFinalConflict'' had an prison inmate who drew alien symbols on his cell with his own blood. They were of huge importance for [[LaResistance the resistance]], as they knew hardly anything about [[SufficientlyAdvancedAlien the Commonality]] at the time.
* In ''Series/{{Elementary}}'', a shooting victim uses his blood to write a message that the shooter was ''not'' his estranged brother, to keep the brother from being a suspect. Other characters point out that given that he took the time to write in his blood, the message is genuine.
* ''HumanGiant'' Has a Paul killing a someone and writing a message on the wall... [[spoiler:Turns out that it's a reminder for Aziz's dentist appointment.]]
-->[[spoiler:'''Aziz''': (''looking at a pile of corpses'') Man, we really need to get a marker board or something. This is [[{{Understatement}} gettin out of hand.]]]]
* ''Series/DropTheDeadDonkey''. Seen during Globelink's so-called 'reenactment' of a post office robbery that (thanks to Gus Hedges desire to recreate ''Film/ReservoirDogs'' instead) gets played for BloodyHilarious {{fanservice}}, including a shotgunned postal worker scrawling I LUV YOU MUM on the wall as he dies.
* ''Series/{{Rome}}''. Lacking a wax seal for a dispatch, Octavian grabs a handful of manure from the battlefield instead.
* {{Subverted}} in an episode of ''Series/{{Monk}}'': Sharona finds a message scrawled in red on a wall...but it turns out that it's just lipstick. [[{{Gaslighting}} Her lipstick]].
* ''{{Series/Salem}}'': George Sibley tries to get a message out indicating that his wife is a witch... by stabbing himself in the thigh and writing on a small piece of paper with his blood. Too bad he gets caught with it anyway.
* In the ''Series/{{Haven}}'' episode "Real Estate", an [[GeniusLoci evil house]] kills a woman, and her dripping blood spells out, "This is your fault."
[[/folder]]

[[folder: Music]]
* Music Videos, to be precise. In the Creator/JohnLandis directed video of Music/MichaelJackson's "Music/{{Thriller}}," we hear:
-->'''Man:''' ... it was a message, scrawled in his own blood.
-->'''Man 2:''' What did it say?
-->'''Man:''' [[AuthorCatchphrase "See you next Wednesday."]]
[[/folder]]

[[folder: Professional Wrestling]]
* During Wrestling/JerryLynn's match with Steve Corino at ''Wrestling/{{ECW}} [=Heatwave=] 2000'', he used Corino's blood as war paint and scrawled the word "DIE" on his own stomach in Corino's blood.
[[/folder]]

[[folder: Tabletop Game]]
* ''TabletopGame/DungeonsAndDragons'' module I12 "Egg of the Phoenix". A revenant [undead creature] will try to communicate by writing a message using its own decaying flesh.
** In the ''TabletopGame/{{Planescape}}'' setting, a cleric of a god of communication once tried to use magic to communicate with The Lady. After [[FamilyUnfriendlyDeath The Lady's shadow had passed over her]], the cleric arose as a vampire that was unable to communicate in any way except by using people's intestines to form words. To compound the problem, a rumour arose that The Lady had indeed said something to the cleric, leading to someone actually seeking her out to find out what. She was apparently happy to comply, but ran out of guts before she could finish.
* ''TabletopGame/{{Warhammer 40000}}'': The scribes of the Grey Knights chapter use blood to write the true names of daemons, as apparently using ink gives the demon some power over the writing.
* Abyssals in ''TabletopGame/{{Exalted}}'' have a Charm that allows them to write in their own blood without suffering any harm from the blood loss.
* There's a power that Harrowed have in ''{{Deadlands}}'' that lets them create spontaneous writing on any surface. The precise effects vary, but making it look scrawled ever-fresh blood is one of them.
[[/folder]]

[[folder:Theater]]
* The German musical ''[[Theatre/{{Mozart}} Mozart!]]'' represents Mozart's genius with a child staying by the actual Mozart's side throughout the play, invisible to everyone else. In the song "[[http://www.youtube.com/watch?v=e_jFhGc0drU Wie wird man seinen Schatten los?" ("How do you get rid of your shadow?"), the way this aspect of him is destroying him is driven home when the child stabs him arm with a pen so that he may continue his composing in blood, draining Mozart's life away.
[[/folder]]

[[folder: Video Games]]
* At least three times in the ''VisualNovel/AceAttorney'' series there has been victims who wrote names, presumably of their killers, in blood. [[spoiler: Twice they were incriminating Maya, and both times they were fake.]] ''Apollo Justice'' has a victim writing a number on the floor in his blood, which is then cleaned by his assassin [[spoiler: because it was a clue that the victim was an Interpol agent]].
** In the case concerning the SL-9 Incident two years before, [[spoiler: Neil Marshall apparently wrote Ema's name in blood on a very unusual vase before he died... but then it turned out it was actually Damon Gant, planting false evidence to blackmail Ema's sister Lana.]]
** There's also the case concerning Maggie, whose boyfriend wrote her name in the sand next to him with his right hand before he died. [[spoiler: He was left handed, and her name is actually spelled "Maggey".]]
** In the first case of ''Ace Attorney Investigations'', another prosecutor finds that the victim (supposedly) wrote Gumshoe's name in his own blood on the crime scene. As Edgeworth, you have to demonstrate that the detective must be innocent.
** The first case of ''[[VisualNovel/PhoenixWrightAceAttorneyDualDestinies Dual Destinies]]'' contains an example that is both a subversion and a straight example. [[spoiler:The defendant's surname is found apparently written by Apollo, who was knocked unconscious, in his own blood. However, the victim of the case had actually written the ID number of her killer, who covered it with a large case; when Apollo found the writing, the killer knocked him out and altered the writing to incriminate the defendant.]]
* In ''VideoGame/ChronoTrigger'', you find a fallen knight who gives you a monster-fighting tip using his blood as the ink. Good thing he was a knight instead of a writer of strategy guides...
* ''VideoGame/DeadSpace'' has "'''Cut off their limbs!'''" written in blood around the ship. It's good advice.
* ''VideoGame/{{Portal}}'' has loads of insane messages scrawled in... Uh, it's hard to tell what it is actually.
** Frosting?
*** We '''[[MemeticMutation all]]''' [[MemeticMutation know]] [[TheCakeIsALie why that can't be.]]
** According to the webcomic tie-in for the sequel, it's just paint.
* ''VideoGame/{{BioShock|1}}'' has a number of messages written in blood, most notably the message on the board of photos reading: [[spoiler: "Would You Kindly"]]
* In ''SystemShock 2'', there are walls with bloody messages urging players to [[spoiler: REMEMBER CITADEL]].
* When you reach Delta Labs 4, the epicenter of the demon invasion in ''[[VideoGame/{{Doom}} Doom 3]]'', the walls are streaked with bloody messages. Whether it was done by [[LegionsOfHell demons]], [[DemonicPossession demon-possessed victims]] or just by [[RoomFullOfCrazy insane victims]], there are no survivors left by the time you arrive. The words repeated over and over again are "suffer", "die" and (appropriately enough for being on the edge of a {{hellgate}}) "burn".
* In the ''VideoGame/MassEffect2'' DLC ''Arrival'', the wall of a prisoner's cell (with the body of the prisoner still in it) has a drawing of the unmistakable silhouette of a Reaper, in human blood.
* In ''VideoGame/WingCommander Prophecy'', it's not shown, but in a discussion between some {{Non Player Character}}s in the pilot's lounge, it's said that the [[CatFolk Kilrathi]] aboard the kat fleet that got wasted earlier in the game used their blood to write "Knathrak", roughly equivalent of Ragnarok for them, on the deck.
* At the end of ''VideoGame/AssassinsCreedI'', Desmond gets to see some [[RoomFullOfCrazy elaborate drawings]] made by [[DrivenToSuicide Subject 16]] in blood. There are so many of them that one has to wonder how he managed to keep the drawings so neat. Although the 'couldn't find a pen' bit is subverted by the fact that [[spoiler: a pen was what he actually used to kill himself. He painted the walls with blood because even after being cleaned away, he knew it would still show up in [[AuraVision Eagle Vision]]]].
* As [[spoiler: Sayaka Maizono]] from ''VisualNovel/{{Danganronpa}}'' was dying [[spoiler: from being stabbed by Leon after she fails to kill him]], [[spoiler: she uses her own blood to leave a DyingClue and help clear Naegi's name.]]
** Later, [[spoiler:when Hagakure believes he killed Sakura, he tries to fake a DyingClue by writing Fukawa's name on a magazine with her blood]].
[[/folder]]

[[folder: Webcomics]]
* FUG's calling card in ''Webcomic/TowerOfGod'' after the murder of [[spoiler: Edin Dan]] and [[spoiler: Gyetang]] was to write the organization's name in big bloody letters on the wall.
* Parodied. When the cast of ''Webcomic/AnsemRetort'' played Pictonary, Axel drew his in Riku's blood for kicks.
* The introduction of the girls in ''Webcomic/CollegeRoomiesFromHell'' has Roger slipping a note under their door. Unfortunately, he forgot to bring a pen, so he wrote the note using blood produced by a convenient papercut. Also, the cut stops bleeding before he can finish writing the message, so what the girls find reads more like a death threat from a stalker than an invitation to dinner (Which is what the note was intended to be).
* In ''Webcomic/{{Homestuck}}'', Vriska mind-controls Tavros into writing text with her blood... for ''him'' to read.
** And then he wears his fingers down, and the writing becomes in his own blood.
** [[spoiler: Gamzee Makara]] has a really fricking creepy variant. [[spoiler: Apparently, after [[SerialKiller he kills off the rest of the trolls]], he is going to paint pictures on the walls with their blood.]]
*** It's pretty impressive to be creepy even by the standards of ''this'' trope.
** When Aradiabot shows the trolls who wrote [[spoiler: the First Guardian genetic sequence]] on [[RoomFullOfCrazy the walls of their rooms]], you can see a wide variety of alternative media and substances in use. Plushie guts, troll blood in various colors, sopor slime...
** Back on Alternia, Nepeta kept an extensive wall painting of all possible romantic pairings between her friends, which she would routinely update, painted in various shades of animal blood. Her theme song is actually called "Walls covered in blood", and is considerably more upbeat than you'd expect.
* In ''Webcomic/{{Juathuur}}'', Rowasu uses blood at the end of chapter 11.
* A particularly awesome moment in ''Webcomic/{{Kagerou}}'' has Dark, bleeding from his [[spoiler: eye sockets]], writing the names of Red's victims in blood, as well as revealing Red's true name, [[spoiler: James Valentine Beethoven]].
* A nanotechnology reservoir in ''Webcomic/LastRes0rt'' is hidden behind a door with some warning scrawled in blood in an alien language.
* In ''Webcomic/SchlockMercenary'', Kevyn Andreyasn uses his blood to write a warning for Captain Tagon, about Kevyn's {{antimatter}} grenade epaulet being armed, as the same injuries that gave him blood to write with also prevented him from being able to speak.
* ''Webcomic/{{Superego}}'' has Juliet do this with milk-based paint, and she does it often, driven by her desire to tell others about her psychic dreams and their potential meanings.
* Done by ''Webcomic/BrunoTheBandit'' in a [[http://www.brunothebandit.com/d/20051031.html parody]] of ''TheDaVinciCode''.
[[/folder]]

[[folder: Web Original]]
* Slightly done in ''DrawWithMe'', where, oddly enough, they use coal on glass, which makes no sense.
** However, it could have been black chalk, and we don't know exactly what the wall is made out of. (It's some durable glass, if it even is some sort of supernatural sentient self-repairing glass.)
* WebVideo/TheNostalgiaCritic, after the ''{{It}}'' review, [[spoiler: [[DrivenToSuicide slits his wrists]] in his bathroom]] and, using [[spoiler: his blood]], writes the word "Balloons" on the wall. [[spoiler: [[UnexplainedRecovery He's fine by the next episode, though]]]].
* In the [[MSPaintAdventures MSPA]] [[InteractiveComic fan adventure]] ''The White Depths'', a cleric blesses a weapon by writing runes on it, but has nothing handy but his own blood. It's just as well though, since [[BloodMagic one's blood is the best vector for a cleric to channel his magic]].
* Mentioned in ''Machinima/FreemansMind''. While walking around some dead soldiers, Gordan thinks to himself it would be funny to write "Latin is a dead language" on the walls with the blood of one of the soldiers, and make it look like he did it as his final act.
* In ''WebVideo/DeathNoteTheAbridgedSeriesKpts4tv'' when Light is [[spoiler: killing Higuchi]] by writing [[spoiler: Higuchi's]] name with his own blood and ends up stabbing himself repeatedly. HilarityEnsues:
-->'''Light:''' First I gotta get my stupid watch open. Aw, there we go...
-->'''L:''' What's that Light?
-->'''Light:''' Oh I'm just excited we caught Kira is all. Hey look, they're bringing him in right now... ''Ow!''
-->'''L:''' Are you okay?
-->'''Light:''' Yeah I'm fin-''OW!'' I'm okay ''OW! DAMMIT!''
-->'''L:''' Light, do you need me to come over there?
-->'''Light:''' No, no. I'm okay. [[DoubleEntendre I'm just so happy that it hurts. Kinda like a little prick.]]
* Played literally in ''WebVideo/ToBoldlyFlee'', where it's revealed that WebVideo/TheNostalgiaCritic wrote [[spoiler: Ma-Ti's will after his death]] using [[spoiler: Ma-Ti]]'s own blood. He blames [[WebVideo/BadMovieBeatdown Film Brain]] for not having a pen on him at the time.
* [[SCPFoundation SCP]][[http://www.scp-wiki.net/scp-012 -012]] is an unfinished composition that {{Brown Note}}s you into trying to finish it this way, until you either bleed to death or kill yourself in despair of not being able to complete it. SCPContainmentBreach includes it as one of the many things that can kill your character if you're not careful, complete with hearing the tune in his head as he bleeds himself to death.
** Another SCP, an unfinished book of a demonic ancient civilization which [[{{Retconjuration}} retcons that race into history as it is written in]], apparently prefers blood as a medium.
* Done in the ''{{WebAnimation/Zero Punctuation}}'' review for ''Thief: The Dark Project''. One of the jokes involves [[Creator/BenCroshaw Yahtzee]] snapping, murdering someone, and writing "{{Press X To Not Die}}" in the victim's own blood on the wall above the body.
[[/folder]]

[[folder: Western Animation]]
* ''WesternAnimation/TheSimpsons''
** In "Principal Charming", Bart wrote his name in the schoolyard using grass-killing chemicals.
--->'''Bart:''' Maybe it was one of the other Barts that-
--->'''Skinner:''' [[OneSteveLimit There are no other Barts!]]
** In "Cape Feare", Sideshow Bob writes death threats to Bart in blood. And his diary. And amusing letters to ''ReadersDigest''. He faints mid way through one of the latter.
--->'''Snake''': Use a '''pen''', Sideshow Bob!
*** Subverted when the family goes over the threat letters and finds one in pen; Homer admits he wrote that one after Bart somehow tattooed "Wide Load" across Homer's ass.
** In "The Springfield Files" Homer runs away from an alien screaming "Yahhh!" As we watch from above we see him run through a field spelling out the word "Yahhh!" in cursive (including the exclamation mark, which he dots!) [[http://www.youtube.com/watch?v=XJuZqumRP70]]
[[/folder]]

[[folder: Real Life]]
* Of the second variety (because it's cool and symbolic), it is general knowledge in Philippine history that members of the [[LaResistance anti-Spanish revolutionary group]] ''Katipunan'' (literally "commune" or "brotherhood") sign their membership forms with their own blood drawn from their forearms as a sign of commitment to the struggle. [[FridgeLogic It was never known whether members suffered from tetanus or infection]], [[RuleOfCool but who cares?!]]
* The Creator/MarquisDeSade, after being imprisoned, wrote his stories on his own body, first using wine and a chicken bone, then his own blood.
* The UsefulNotes/MansonFamily had a creepy habit of writing things on walls at murder scenes - in the blood of the victim.
* The murder of Frenchwoman Ghislaine Marchal in 1991 involved her writing in her own blood on a wall: "Omar m'a tuer" ("Omar killed me", with a glaring spelling mistake†− despite the victim being a ''French teacher''.) The phrase is still very famous in France (perhaps due to the controversial nature of the whole thing: The case is still sort of unsolved).
* Apparently, several people have made last-minute testaments in this way: There is a story about a farmer, trapped under his own tractor writing on the bumper, with mud, who of his neighbours would get which of his animals and about a dying man who wrote "all to wife" on the wall in his own blood. Both of these were accepted as valid.
* ParentheticalGirls are hand-numbering their latest album in their own blood.
* A man in Pinellas, Florida tried to invoke this trope after murdering his girlfriend by writing the first name of his victim's ex-boyfriend on the wall in her blood, creating the impression that she wrote her killer's name as she died. His ruse failed when the police took a closer look at the victim's injuries and realized that she would've been physically incapable of pulling it off, not to mention the blood was on her right hand and she was left-handed.
* Saddam Hussein had [[http://en.wikipedia.org/wiki/Blood_Qur%27an a copy of the Qur'an written in his own blood]]... [[CriticalResearchFailure even though blood is seen as unclean in Islam]] and [[ComplimentBackfire writing a Qur'an with it is a very high blasphemy]]. Of course, [[MortonsFork destroying any copy of the Qur'an is also blasphemy]].
* IIRC, the guy who wrote the lyrics to the [[CrowningMusicOfAwesome Moroccan national anthem]] wrote it in his blood on his cell wall. It must have looked like a RoomFullOfCrazy.
* [[{{Geocaching}} Geocachers]] who hike several miles to a cache to realize they left their pen in the car have been known to sign the logbook in blood. The preferred way is to make a mark with dirt or mud and explain it in your note online.
* Apparently, this was once inverted: The murder victim had a pen and wrote the killer's name on her body. Unfortunately, the conditions the body endured made it unreadable until the FBI's Special Photo unit used an infrared camera to get a better image. The guy was caught.
* When Fracisco Pizarro - the Spanish conquistador who led the conquest of Peru - was assassinated, he was stabbed through the throat. Reportedly he drew a cross in his own blood and kissed it before dying.
* When the last Mughal Emperor (who was a noted poet) was exiled from Delhi by the British for supporting a major rebellion, he wrote poems on the walls of his room with a burnt stick.
* Anthony H. Wilson, head honcho of Factory Records, had several contracts (most notably that of Joy Division) written in his own blood - not for want of a pen, but because he was ''batshit insane''.
* Sergey Yesenin, one of the best Russian poets of the early 20th century, wrote his last poem ''Goodbye, my friend'' in blood. He complained to a friend that day: "This mangy hotel has no ink. I had to write with blood," and showed 3 shallow cuts on his wrist. Yesenin was very depressed (therapy didn't help) and hanged himself the next day, it's possible that he started to slit his wrists, but [[BungledSuicide changed his mind and wrote the poem instead]]. A series of [[FollowTheLeader copycat suicides]] followed with crappy poetry written in blood.
[[/folder]]

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