Bob is about to do something that Dave considers stupid. He's going to attempt a Heroic Sacrifice, or otherwise put himself in danger. At this point, Dave could try to reason with Bob, but Dave has a better idea.
He punches Bob in the face. (The gut and/or solar plexus are also popular areas.)
Nine times out of ten, this will render Bob unconscious, and if it doesn't, it subdues Bob long enough for Dave to take Bob's place or remove him from danger. Dave may get yelled at for this or punched in return if Bob is really put out, but Dave will most likely respond that he did what he had to do.
A subtrope of Cruel to Be Kind, since knocking your friend over the head is not something that sounds positive out of context.
Anime and Manga
- In One Piece, Luffy knocks out Mayor Boodle when the old man tries to challenge Buggy the Clown. In a later episode, Zoro knocks Sanji out to keep Sanji from effectively sacrificing his life to a high-powered government thug in Luffy's place.
- In Eyeshield 21, Homer punches Panther in the face to prevent him from attacking their racist coach, which would get him kicked off the team and possibly out of the school. In a later episode, Tetsuma smacks Monta around to keep him from going ballistic on the referee and getting his team thrown out of the Fall Tournament.
- In Dragonball Z, Vegeta knocks Goku, Trunks and Goten out (In that order) to keep them from fighting Buu.
- In the alternate future, Future Gohan knocks Trunks out to keep him from fighting the androids. By the time Trunks wakes up, Gohan is already dead.
- And in the Abridged Series, Goku does this to Jeice while Jeice is giving a monologue. Only Goku wasn't trying to stop his speech, he was trying to get Jeice to fight.
- Happened to Naruto on the second movie.
- In the Naruto main series, Hyuuga Hiashi's twin brother Hizashi knocks him out with a punch to the solar plexus in order to take his place as a human sacrifice.
- In Angel Sanctuary an already dying Kira punches Katou in the stomach in order to essentially commit suicide. Or maybe it was just a case of Taking the Bullet, but you know the drill.
- In JoJo's Bizarre Adventure, Kakyoin shoots Polnareff with an Emerald Splash to knock him out of the way of Hol Horse's bullet.
- Bleach Soul Society arc.
- While getting Orihime away from the scene of a battle between Uryū Ishida and Captain Kurotsuchi, a Soul Reaper knocks her out to keep her from going back to help Uryu.
- When Ichigo tried to confront Captain Kuchiki outside Rukia's place of imprisonment, Yoruiki rendered him unconscious and escaped with him. She knew he wasn't strong enough to fight Captain Kuchiki yet and would just get himself killed.
- In Inuyasha, the "sharp shot to the solar plexus" move was once used by Miroku to subdue a peasant girl whom he was trying to move to safety.
- Done a few times in Keroro Gunsou, like in episode 2 where Keroro drops about a dozen metal wash basins on Momoka's head to stop her from pelting Tamama with volleyballs... and thus prevent her from provoking Tamama into retaliating violently.
- Great Teacher Onizuka has Onizuka put bossy, self-righteous Vice-Principal Uchiyamada in a German Suplex for trash-talking some angry delinquents he'd had expelled from school. Which pacifies the delinquents and prevents them from doing anything worse to Uchiyamada.
- Used occasionally in Fairy Tail, usually by Gray and Natsu on each other when one of them is too injured to fight but too stubborn not to. Erza also employs this on Natsu once to save him the pain of crippling motion sickness.
- Natsu inverts this on Erza, knocking her out with a punch to the stomach in order to fight Jellal for her.
- In Nintendo Power Comics' version of the Star Fox story, Falco knocks out Fox to prevent him from attempting to fly though the black hole, and offers to go in his place, arguing that Fox is a better dogfighter, but he [Falco] is a better pilot.
- In one of the only times that he hits a woman, Marv from Sin City does this to Wendy in order to spare her from watching him torture her sister's killer to death, something that would "give her nightmares."
- Lucille, Marv's parole officer, does the same to Marv earlier on to stop him from fighting the cops after the escape from the farm, saying that she's not going to let him get either of them killed. Unfortunately for Lucille, the cops sent to the farm turn out to be a death squad who proceed to murder Lucille after she tells them what she knows.
- During Walt Simonson's run on Thor, Thor, Balder and Skurge (a former Thor villain known as the Executioner) lead an army of souls in a daring escape from Hel, the Norse underworld. The souls must cross the bridge of Gjallerbru, with an army of demon warriors on their heels. Thor orders Balder to lead the souls to escape while he holds the bridge. Skurge knocks Thor out and tells Balder, "You and Thor have a drink when you are next in Asgard and laugh Skurge's last laugh together. I will hold the bridge." Skurge then holds the bridge with two M-16s, going down in what can only be defined as a Crowning Moment of Awesome. Or, to quote the closing narrative;
They sing no songs in Hel, nor do they celebrate heroes. For silent is that dismal realm and cheerless.
But the story of the Gjallerbru and the lone god who defended it is whispered across the Nine Worlds. And when a new arrival asks about the one to whom even Hela bows her head, the answer is always the same.
He stood alone at Gjallerbru. And that answer is enough.
- During an arc of Justice League of America, Captain Marvel punches out Superman in order to take his place on a trip to the 5th Dimension, where Captain Marvel's abilities are somewhat better suited to the task.
- In the classic Sun-Eater storyline in The Legion of Super Heroes, Ferro Lad knocks out Superboy and takes the bomb into the heart of the monster in a Heroic Sacrifice, knowing that the red sun radiation from the Sun-Eater would have rendered Superboy vulnerable to the bomb.
- During a Walt Simonson arc of the Fantastic Four, Reed Richards refuses to escape from a site targeted for imminent destruction without rescuing Sue and Johnny first, prompting Ben Grimm to knock him out and cart him off to safety. After the place blows up and (apparently) kills the Storms, Reed predictably flips out at Ben, who justifies his actions in an unexpected reversal of their usual Red Oni, Blue Oni roles by reminding Reed that while the two of them would would have gladly died rather than leave Sue and Johnny behind, the entire universe is about to be annihilated and without Reed, the others along for the ride—Thor, Iron Man, and Ms. Marvel—would have no chance in hell of saving it.
- Who Framed Roger Rabbit?: Jessica Rabbit hits Roger with a frying pan to keep him out of harm's way. It does make perfect sense for Roger, who is only temporarily incapacitated by physical violence, to keep him out of the way of villains using Dip, which could kill him.
- Sky Captain and The World of Tomorrow: Joe punches Polly to stop her from helping him destroy an art-deco flying rocket-ship ark. Subverted, as she isn't really knocked out, and ends up saving his ass...right before punching him back.
- Tremors. Valentine elbows Earl in the stomach to stun him so Valentine can risk his life running to the tractor to save everyone (and risk being killed by the Graboids).
- One of the big scenes in Shane. Except instead of going down with one punch, Shane and Starrett end up in a knock down drag out fight to see which one of them gets to ride into town and face down The Gunslinger that's been hired to kill Star.
- They Live! has a scene similar to this, in which two friends proceed to beat the crap out of each other for a full five minutes over one getting the other to put on a pair of sunglasses that let the wearer detect all the hidden brainwashing messages in popular media.
- This is largely Fan Service. One of the characters was played by Roddy Piper, and they were doubtless expecting a lot of pro wrestling fans to be watching.
- The Punisher: War Zone movie has Frank doing this to a character before going in a house full of armed crooks.
- Van Helsing was originally going to punch Anna Valerious in the face to keep her from going out to hunt Dracula. When watching the dailies, director Steve Sommers realized how bad this looked, and reshot the scene so that Van Helsing used a spray of knockout gas instead.
- At the climax of Star Trek II the Wrath of Khan, the Enterprise's warp engines are damaged, and repairing them would require exposing someone to large amounts of radiation. Spock immediately heads to the engine room to try to make the repairs himself. McCoy attempts to stop him, but Spock nerve-pinches him and ends up sacrificing his life so the crew can survive.
- Parodied in the movie Almost Heroes. Chris Farley's character attempts to do this to another character, but it doesn't knock him out. After he starts to pick up a big rock, he's told to just go ahead.
- In Pirates of the Caribbean: Dead Man's Chest, Elizabeth fights her way through a Bar Brawl started by Norrington in order to knock him out before he gets himself killed by the other bar patrons.
- In The Thin Man (from 1934!), Nick punches Nora out cold to get himself (and her, and Asta) out of a sticky situation. She's not too happy when she comes to, but she lets him off the hook when he explains. Then they have a drink together.
- Armageddon: A.J. (Ben Affleck) has to be the one to remain on the asteroid and detonate the bomb, after drawing the short straw. Instead, Harry (Bruce Willis) disconnects an oxygen tube from his space suit, forcing him to go back to the shuttle and let Harry do the job.
- In Animorphs #46, Ax knocks out Jake so that Jake won't have to bear the responsibility for Ax's plan to threaten Visser Two with the nuking of the Yeerk Pool (and therefore, the Animorphs' hometown).
- BattleTech: Galen Cox slugs this trope in Victor Steiner-Davion's face when he is determined to return to the battlefield to save his command. He wakes up in a dropship leaving the atmosphere of the planet he was assigned to for safety.
- Discworld: Vimes does this in Night Watch at one point to stop his younger self from getting himself killed.
- Lelldorin in the Belgariad mentions to Garion, while describing his (Lelldorin's) flight from Vo Mimbrae, that he punched out a friend of his "because I didn't want to hurt him". (If the friend had had the chance, honor would have demanded he fight Lelldorin to the death.)
- A Storm of Swords: Sandor Clegane knocks Arya unconscious with the flat of an axe to keep her from charging into the Red Wedding in a suicidal attempt to save her brother and mother.
Live Action TV
- On The X-Files, Scully shoots Mulder to keep him from killing Krycek.
- Star Trek: The Original Series:
- In the Star Trek: Deep Space Nine episode "Once More Unto the Breach", when Worf prepares a suicide mission to protect the crew of a Klingon ship from the Dominion, Kor knocks him out and does the Heroic Sacrifice.
- Mystery Science Theater 3000 episode "Puma Man" has the inscrutable Aztec hero knock out the Designated Hero so that Aztec can go on a suicide mission alone.
Crow T. Robot: Yes! The Aztec speaks for all of us!
- Doctor Who, "Forest of the Dead": River Song knocks out the Doctor to prevent him from sacrificing himself, and takes his place instead.
- A similar thing happens in the 4th season episode "The Poison Sky". The Doctor's going to go and destroy the Sontaran ship, and Luke Rattigan quickly gets his own teleporter working, teleports up, knocks the doctor back into the teleporter and destroys the ship himself.
- The original series did it as well, in "The Ark in Space", when The Doctor and Rogin, a space technician need to decide who stays and gets killed when the rocket they're working on blasts off.
Rogin: You don't want trouble with the Space Technician's Union, Doctor! * Thump* That's my job!
- In "Battlefield", the Brigadier one-punches the Seventh Doctor and faces the Destroyer on his own.
- Buffy the Vampire Slayer applies some Percussive Prevention to her watcher, Giles, on more than one occasion. The original was in the first-season finale, wherein after Buffy has her Ten-Minute Retirement over her prophesied death and the associated She's Back moment, Giles tells her he is going to face the Master in her stead, and "there's nothing you can say that can change my mind." Buffy replies that she knows, and then roundhouse punches him. Thud.
- In Farscape, John fails to resist Scorpius, gives up and tells Aeryn he's going to turn himself in. Aeryn knocks him out.
- In Lost, Charlie knocks out Desmond when he tries to take his place swimming to the underwater Dharma station.
- In Highlander the Series, Methos once shot Duncan in the heart to keep him from participating in a duel where he was sure to get killed. This being Highlander, Duncan was none too pleased when he healed up.
- Hornblower (1998 – 2003): In "The Even Chance", Mr Midshipman Clayton does this to Mr Midshipman Hornblower just before Hornblower is due to go fight a duel with Mr Midshipman Simpson, knocking him out with a pistol butt and taking his place as his second. Simpson is wounded, Clayton is gutshot, living just long enough for Hornblower to come round, reach the shore and listen to his Last Words.
Later in the same episode, when Mr. Midshipman Kennedy is suffering a seizure while they attempt to sneak up on a French warship, Mr. Midshipmen Hornblower gives him a Tap on the Head, before leaving the unconscious man in the boat while they board the ship. Mr. Midshipman Simpson casts the boat adrift and we don't see the man again until two episodes later.
- Most everybody in Smallville. Do they have a trauma ward in that hospital?
- On Oz, in the long feud between Beecher and Schillinger, Schillinger gets his son to kidnap Beecher's children and kill one of them. In retaliation, Beecher arranges to have Schillinger's son killed, but feels remorseful afterwards. So remorseful, in fact, that when Schillinger is about to find out that Beecher was responsible Beecher decides to own up to it. Keller wants to confess to the crime instead so that Beecher won't become a target. Beecher tells him no. Keller knocks Beecher out so that Beecher can't stop him from taking credit for the murder and then runs off to do so.
- Game of Thrones has an episode where Tyrion Lannister (who has never participated in a battle) is about to do such but, even after an emotional night after coming to terms with the potential of his death, is luckily knocked out by one of his own soldiers accidentally mere moments before the battle begins.
- Modesty Blaise: In "Milord", Willie knocks Modesty out so cannot interfere with a group of women taking their revenge on the men who raped and tortured them.
- In Everyday Heroes, Mr. Mighty knocks out Iron Jane to prevent her from committing murder for revenge.
- In Homestuck, Dave and Rose get to arguing about which of them will undertake a suicide mission involving a giant bomb. Rose eventually beans Dave with her magic yarn ball to make him fall asleep, so she can go on the mission alone.
- Hawkgirl to Hawkman in Justice League Unlimited.
- Parodied on The Simpsons, when Homer tries to stop Barney from driving drunk by knocking him out. After getting whaled on with fists, a tire iron, and finally having his head slammed repeatedly in a car door, Barney remains very much conscious and a little bit confused at what Homer is up to.
Ow! Cut it out. Ow! Ow! Ow! Ow! Ow! All right, here, take the keys.
- In the World War I-set Looney Tunes cartoon "Dumb Patrol", Porky Pig was selected for a dangerous air mission, but Bugs Bunny dropped a brick on his head.
"Y'know, I just had to take his place. He's got a wife and six piglets."
- Metal Gear Solid
- Metal Gear Solid 2: Even Mission Control suggests that you knock E.E out and drag her in order to get past some scary bugs on the floor.
- In Metal Gear Solid 3 punching out Eva and dragging her is the best way to keep her from doing something stupid that might attract enemy guards. Also saves on food since her stamina doesn't go down while asleep.
- Happens twice in Suikoden II once early in the game, Tsai of the Holy Spear may knock out two of the main characters to preventing them from fighting against Luca Blight, and later on the game Flik knocks out e major of Greenhill to prevent her turning herself in to the enemy army.
- In the finale of Captain Rainbow, the island is facing destruction, and Hikari tells you to escape on the last wishing star. You can refuse, but Hikari will still insist you go. Since she won't take no for an answer, you knock her out, put her on the star and send her off to safety.
- AKA "The Duel"