Pit: Are you talking about the floating skull?
Palutena: Yes, the slightest touch from one of those will annihilate you.
Pit: That sounds painful. Not to mention totally unfair!
...which is why these enemies are particularly shocking...
Instakill Mooks are mooks that can knock the Player Character from full health to 0 in just one blow. Unlike with other mooks, the player can't afford any mistakes. This means the game can go from "doing very well" to "restarting the level" in just a few seconds. For that reason, these enemies are almost always feared by players.
The second is when an enemy simply instakills no matter how much HP the playable characters have. These will not show damage counters even in games that have them. If they do, it is likely an infinity or a skull symbol.
The third is when there is a One-Hit Kill technique common throughout the game that is known by many different enemies. These enemies and techniques are usually either incredibly holy or dangerously evil. Either way, the technique is often strictly forbidden. Scientific methods of insta-killing are also possible, such as massive lasers and Disintegrator Rays.
When an enemy can one-shot the player simply because of being a higher level, it does not count for this trope. The enemy must be able to end a character of the same level in one blow. Taking on vastly higher-leveled enemies is either a Self-Imposed Challenge, getting completely lost on the map, or just being stupid. Everyone knows that the level 1 character cannot fight the level 30 mooks; everything will instakill it.
When every enemy is this, the player character is a One-Hit-Point Wonder.
Subtrope of One-Hit Kill. Enemies like these are almost always Demonic Spiders. Compare Ledge Bats, which don't instakill by themselves, but rather by making you fall onto Bottomless Pits. Contrast Invincible Minor Minion, the mook that you just can't kill.
- Avencast: Rise of the Mage: The labyrinth beneath the Avencast Wizarding School is patrolled by Magitek drones, whose Wave Motion Gun instantly kills the Player Character. Fortunately, they're Glass Cannons and the deadly attack takes a second to charge up.
- Mass Effect:
- Mass Effect 3: Each Faction (except the geth) has at least one enemy able to perform a "Sync Kill"—an unblockable melee ability that leads a dead player that's unable to be revived. The Reapers possess both Brutes and Banshees, Cerberus possesses Phantoms and Atlases, and the Collectors possess Praetorians (Possessed Abominations can also One-Hit KO the player by exploding upon death, but this can be revived). The only playable character immune to Sync Kills is the Geth Juggernaut.
- Mass Effect: Andromeda: Sync Kills return in this game, with characters such as the Kett Ascendants and Fiends, or the Outlaw Hydra, able to perform them. The Remnant Faction lack this mechanic like the geth before them, but a Destroyer can produce a post-mortem explosion than can one-shot any player unfortunate enough to be in the area.
- Monster Hunter Frontier has the Egyurasu, the flunkies of Guanzorumu that can pick up Hunters and throw them off the arena for an instant kill.
- In Fallout 4, Deathclaws have a new instant-kill Neck Snap move, which Power Armor protects against, while an Assaultron's Wave Motion Gun will immediately burn the protagonist to ashes even if they are in Power Armor.
- In The Legend of Zelda: A Link Between Worlds, Lynels become this in Hero Mode, as they now deal twelve whole hearts worth of damage per hit. The max is twenty, and that's with 100% Completion. By the time you actually meet the Lynels, you'll still be well under ten hearts.
- The Legend of Zelda: Breath of the Wild: Enemies in the Yiga Clan Hideout will kill Link in a single hit no matter how much health and armor he has. They also bypass faeries, Mipha's Grace, and the game's usual Anti-Frustration Feature that prevents Link from being killed in one hit if he's at full health even if the attack deals more damage than his maximum HP. This is because the segment is intended to be a Stealth-Based Mission -the enemies kill you instantly to encourage sneaking around them rather than trying to fight. However, it is possible to complete the hideout without stealth if the player is skilled and careful enough.
- In Steve Crow's ZX Spectrum games Wizard's Lair and Starquake most enemies drain health, but some will cause the player to lose a life. In the former game, the dangerous mooks are the 'knight' and 'executioner'; in the latter they're mobile mines which resemble spinning tops.
- Dragon's Crown has one in the form of the KillerRabbit, if you get hit by the rabbit's attack while it Turns Red, it deals damage equal to the player's maximum HP bar. And to emphasize this, an x-ray of a cracked skull appears over your character. So, the only means to survive this is by NOT getting touched by it (or if your HP is above the maximum).
- OMEN-XR-wielding thugs in the last level of Goldeneye Rogue Agent. They also have Electromagnetic Shields. It is possible to break through their shields with enough firepower, but getting rid of them is almost impossible. Almost. Thankfully, there are only about one or two of them on each floor. (And sometimes the cowards get a couple of guys with Venom guns for extra support...)
- In Halo 2's Legendary difficulty, the Sniper Jackals kill you instantly no matter where they hit.
- In First Encounter Assault Recon, the Type 7 Particle Weapon skeletonizes human targets in one shot. This includes the Pointman.
- In Soldier of Fortune, a single charged shot from the Microwave Pulse Gun will instagib Mullins. Fortunately, enemies who wield the weapon are extremely rare.
- Multiple in the Super Mario Bros. series.
- Throughout the series, there are fish enemies called Cheep Chomps. These enemies often devour Mario in one bite, even in the New Super Mario Bros. series, where every other enemy just knocks off his powerup.
- In Super Mario Galaxy and its sequel, Super Mario Galaxy 2, crushing damage is instantly fatal even though everything else takes three hits to kill. This means that the golem-like Thwomps and Whomps play this role.
- Pouncers can one-shot Wario in Wario Land: Super Mario Land 3, regardless of powerup state. Even if you merely bumped into its sides. This is because the sides and bottom are spiked, and spikes are an instant kill to Wario.
- In Cave Story, there is an enemy that appears early in the game called a Basil. It moves incredibly fast, is indestructible, and deals 100 damage, which is far more damage than you can have health in the game.
- The Smurfs (1994) had the Bzz flies and Black Smurfs, whose sting/bite instantly turned you into a Black Smurf.
- Mega Man 5 had the drill enemies in Napalm Man's level. They advance towards Mega Man, and touching them would destroy Mega Man instantly regardless of health.
- Pikmin :
- Electricity can kill the eponymous Pikmin instantly, so any enemy attack based on this element is lethal. Same with bombs and any other explosive attack. Good thing Yellow Pikmin can use bombs in the first game and resist electricity in the second. Also, in the third, electricity is nerfed so that it can only stun non-yellow Pikmin.
- During the later fights with the Empress Bulblax, there's her offsprings, the Bulbord Larvae. They die in one hit, but also kill Pikmin in one hit (as well as deal a good chunk of damage to the captains), and they do it fast. Given how the Empress Bulblax also constantly gives birth to the little buggers, they can become deadly if left unchecked. A captain can distract them to leave the other free to attack the Empress, but that can be easier said than done.
- Shin Megami Tensei has several One-Hit Kill spells that are used by regular enemies:
- Hama, Mudo and their variants. Any mook can have them as soon as you start the game, and yes, they are very effective. Hama is usually owned by Divine (read "Angel") type enemies, while Mudo belongs to ghosts, hell-themed demons etc. However, Hama gets Nerfed in a few games.
- Any enemy that can deal the "Stone" status ailment. If anyone inflicted with it is hit by a physical, Earth or Force attack, they die. In some games, if the hero is petrified, the game ends instantly even if you had demons who could heal him.
- Many - usually late game - enemies have the following pattern: a skill that inflicts a status effect, and a second skill that kills anyone who has it.
- Persona 1, on top of all the Hamas and Mudos has Deathtika - usually owned by toilet-inhabiting ghosts - and Hell Eyes (owned by somewhat freackish enemies). Then there's "Self-Destruct", the Mutual Kill spell.
- In Persona 2, most human enemies come with the skill "Sharpshoot/Aimed Shot", which deals gun-based instant kills. Other examples include "Pressure Point/Needle", "Omega Cluster" (used by late-game mooks), "Bright Judgement" and "Dark Verdict" (also by late-game mooks). Finally, a rare few enemies have "Omni Dimension".
- Miitopia: Fiends are deadly enemies with scythes. They have two attacks, either a physical attack that deals only 1 damage, or a magical attack that deals 999; far more than any Mii character can survive. Terror Fiends are similar only they have more health. 666 to be exact.
- In LISA: The Painful, most Joy Mutants (with the exception of Doctor) have either Neck Break, Fatal Chomp, or both. These attacks permanently kill your party members in one hit, so extra caution is advised when fighting them.
- Final Fantasy
- There is one enemy called 'Sorcerer' (named 'Mind Flayer' in the remakes) whose physical attacks inflicted only Scratch Damage but with a side effect of instant KO — pray they don't get to strike first when you encounter a group of 5. The ProRing, despite being obscenely expensive, protects against instant death, and renders Sorcerers completely impotent, but the game doesn't tell you that, ever.
- The recurring Tonberry enemy has the signature Karma attack. This one attack deals damage based on how many enemies you've slain over the course of your journey. Given that the heroes are bound to have slain hundreds if not thousands of enemies over the course of the game, there is little hope of surviving an attack from a Tonberry. It will always use this attack in response to being attacked, so if you're going to fight a Tonberry, it better be a One-Hit Kill. Many games also have it possess the Chef's Knife ability, which deals massive damage or just plain kills the target outright and the Tonberry doesn't need to be attacked to use it.
- Final Fantasy IX: Yan are an enemy limited to one specific part of the world map and the most dangerous in the game, despite their adorable looks. In particular, they possess the ability to cast "Snort" an ability that permanently ejects one player character from the fight. That character is effectively "dead" with no way of recovering them and Yan have incredible speed, meaning that all of them may get their turns (if not multiple) turns before the player can finish inputting their own, thus making it very likely that all three characters will be "Snorted" out of the fight and lead to a Game Over.
- In Grandia II's Bonus Dungeon, there is an enemy called Devil that can cast the spell BA-BOOM, which always hits your entire party and deals more damage than you will ever have HP.
- EarthBound Beginnings and EarthBound features a number of enemies capable of casting Petrification and Diamondization, respectively. Getting hit with this PSI (described in EarthBound as the enemy "glar[ing] with its eerie eye") counts as an instant kill for the target; getting one's entire party Petrified/Diamondized will result in an instant Game Over. Conversely, in EarthBound it's possible (via confusing the enemy or using Poo's Mirror ability) to have an enemy Diamondize either another enemy or themselves; this includes bosses capable of Diamondization. A Petrified/Diamondized party member will drag behind the rest of the party as a dead weight, appearing as a static sprite (when Petrified) or an orange anthropomorphic gemstone (when Diamondized), just as a reminder that they're definitely not gonna contribute to a fight anytime soon. A Diamondized enemy, meanwhile, will stay on the battlefield during a fight, but will be counted by the game as defeated and will disappear from the overworld as normal after the fight; if the last enemy defeated in battle is done so via Diamondization, it'll create an amusing situation where they'll stay on-screen while the game displays the standard victory text. Petrification and Diamondization can be cured via healers, PSI Healing γ, or (in EarthBound) PSI Healing Ω.
- EarthBound Beginnings also has enemies that can cast PK Beam γ, which is a one-hit kill against any party member who lacks the Franklin Badge in their inventory. These kinds of enemies appear even before the second party member joins, so if you neglect to get the Franklin Badge (which isnt obvious), you could be in trouble.
- Pokémon : Any wild or trainer Pokemon with a One-Hit Kill attack can be one of these. Thankfully, if your Pokemon's level is higher than theirs or has a type immunity to the attack, it'll fail. Even then, said attacks tend to have very poor accuracy.
- Kid Icarus: Uprising:
- Ornes are this combined with Invincible Minor Minion. Fortunately, they don't have any ranged attacks, don't usually come close to Pit, and die when all other enemies in the area are defeated.
- There are also Tempura Wizards, an upgraded version of the Eggplant wizards. While Eggplant Wizards "just" turn Pit into an eggplant and render him helpless to attack, Tempura Wizards turn pit into tempura shrimp, and then try to eat him. If they catch him, you lose.
- In Hard Corps: Uprising, enemy snipers will attempt to lock onto you, and if you get caught in the crosshairs, they'll fire a bullet that does 4 points of damage if it connects, enough to kill any character in Arcade mode but it can be survived in Rising mode thanks to life upgrades (most other attacks only deal one point of damage to your Life Meter).
- In Splatoon 2, in Salmon Run, Maws, like the Octomaw, can try to eat your Inkling whole, but sometimes, if physics favors you, you can get out of being swallowed.
- In The Last of Us, melee combat with Clicker type Infected is generally not advisable, as they go straight for the jugular if they grab you. You can, however, learn a skill that allows you to escape the deadly grasp of a Clicker, with a shiv and good reflexes. Bloaters as well, although unlike Clickers, there is no skill to save you, and you're in for a bit of a shock if they get you...
- Resident Evil:
- The earlier games had Neptune, who would swallow the player whole, the Hunters, who could decapitate the player, and Nemesis, who could impale his victims through the head, among others.
- Resident Evil 4: The chainsaw-wielding Dr. Salvador and Bella Sisters are able to instantly kill Leon by decapitating him.
- Likewise with their Resident Evil 6 counterpart, Ubistvo (which is Serbian for "murder"), which can kill whichever playable character confronting it with its own bio-organic chainsaw. It's also an Implacable Man that must be fought several times before it's put down for good.
- Resident Evil: Revelations introduces the Scagdead enemy, which will cause one of these when caught by its' jaw attack.
- In the Syphon Filter series, explosives, headshots from snipers, and contact with burning enemies all result in instant death for the player character regardless of their armor and HP levels.
- In Max Payne 3, sniper shots and rocket-propelled grenades are guaranteed instadeath with no Last Man Standing opportunity.
- Inverted with the Fire Emblem series, where the Assassins - whom possess a skill to inflict a One-Hit KO based on their critical hit chance - are almost exclusively playable characters. In the rare instances they appear as enemies, they're equipped with a weapon that prevents them from unleashing any critical hits, including One-Hit KOs. The reason for this is that the franchise operates on the All Deaths Final rule: when a character dies, they stay dead.note Therefore, an enemy that can take out a playable - and potentially invaluable - character in one lucky strike will cause players that much more frustration, not that the games are easy to begin with.
- Mini Robot Wars has the Giant and Titan, both of which are Giant Mook enemies that instantly crush any Minirobot they hit. The latter can crush up to three Minirobots in front at one go. The Capsule Cages will abduct any Minirobot they land on if not removed in time, thankfully they have low HP.
- Plants vs. Zombies: The Zomboni and Catapult Zombie instantly crush any plants they run over with the exception of Spikeweed/Spikerocks which instakill them instead, the Jack-in-the-box Zombie explodes all plants in an area (including Spikeweed/Spikerocks) around it if it triggers, the Bungee Zombie instantly abducts plants, and the Gargantuar and Giga-Gargantuar crush any plants in their way unless it's Spikerock, which can take three hits.
- Plants vs. Zombies 2: It's About Time introduces several, besides the usual Gargantuar variants. The Explorer Zombie burns units with his torch, the Pirate Captain's Pirate Parrot can instantly abduct a plant that isn't low-lying, the Mecha-Football Zombie pushes entire rows of plants back with the one nearest your house being thrown away, the Surfer Zombie uses his surfboard to crush your plants, the Fisherman Zombie can drag your plants into the water, the Troglobite can push ice blocks onto plants, the Excavator Zombie can shovel them off the lawn, the Turquoise Skull Zombie can annihilate a line of plants with a sun-powered laser, the Punk Zombie can kick plants off the lawn if there's no space when his Jam is playing, the Glitter Zombie instantly crushes plants she runs over when her Jam is playing, the Arcade Zombie can push his arcade cabinet onto your plants, the Rockpuncher Zombie can instantly crush plants while leaving unplantable craters behind, and the All-Star Zombie has a tackle attack that instakills a plant. The Barrel Roller, Pianist and Hamsterball appear to instakill, but actually deal very rapid damage over a short period of time, while MC Zom-B and Rodeo Legend just deal an incredible amount of damage per attack.
- Minecraft: The explosive creepers can be this if explosion is point-blank and your character is armorless.
- In Red Dead Redemption II, Cougars and Panthers have a pounce attack which, if it lands, will instantly kill the player character regardless of health. There's also the hidden snipers who one-shot you if you go out of bounds.