That One Attack/Video Games/Role-Playing Game/Shin Megami Tensei

Examples of in  include:

Persona 1

 * Butterfly Storm from . Large damage and status ailments.

Persona 2

 * Terror Fortune from . See above.
 * Bloody Divorce from : Huge Water Damage, and high chance of instant death.
 * Hula of Misfortune: Watch a hula-dance, lose half of your total money. You don't get it back.
 * Aimed Shot: Chance of instant death. One boss battle has his four elite mooks spam this on end.
 * Kudan's attack "Prophecy" kills the monster in question, but it will revert all of your active Personae to Rank 1 and remove any mutations they received. And it doesn't wear off.
 * In Innocent Sin: Mephistophiles. Random statuses to your entire party. And it's the opening move of a Chest Monster.

Persona 3

 * Night Queen from . Sizeable damage, devastating status ailments. If it happens to Charm your healer, get ready to fight the last form from the beginning.
 * On the other hand, if it happens to charm someone else, don't be surprised if the last vestiges of thine HP are wiped by any of many fun weapons.
 * On the same boss: "Moonless Gown." Not an attack, per se, but brutally unfair nonetheless. Not only does it make it entirely immune to damage (even almighty damage) for a couple turns, it also reflects that same damage back to you. The final boss of Persona 3 is a monster.
 * Not to mention that, in a truly irritating display of Artificial Stupidity, your allies will blindly attack the Moonless Gown unless you stop them, even though both Fuuka and common sense say that they shouldn't. This can be especially brutal if you've had to revive any of your allies, in which case they take their turn before you do.
 * The obvious answer to the above is to use your teammates that are immune to the same elemental spells that they cast, right? Wait, no, the boss just uses the appropriate Break skill to remove their immunity. And you thought you were so clever.
 * The Mythical Gigas' Deathbound hits everyone for a huge amount of Strike damage. It's about 300 damage if it doesn't critical (you'll probably have 480 HP, tops, by the time you reach him), and if it criticals, that number can easily exceed 1000, and no amount of Level Grinding will allow you to survive when that happens.
 * Dark Embrace from Persona 3 FES's . When it uses this attack, unless you manage to deal enough damage in time, it'll deal a good amount of damage to you. Survivable at first, but it gets stronger throughout the battle, so when you see it charge up Embrace, throw everything you have at it.

Persona 4

 * has World's End, which is game-ending if you can't figure out how to avoid it. Huge damage to your entire party, chance of status ailments to everyone. She also follows it up by immediately using Summons to Yomi, which kills any character with status ailments.
 * Rampage, used by the Contrarian King. Hits your whole party up to 3 times for huge damage and will one shot your entire party if you fight him as soon as you can.
 * Kunino-Sagiri's Control, which brainwashes one of your characters. They do the same things as they would if they were Charmed, but 1: it's unavoidable, and 2: it's incurable; you have to wait it out. After Kunino Turns Red, he'll take control of three of them. Just pray they don't use Diarahan.
 * Stagnant Air increases everyone's susceptibility to ailments by at least 50%, which then makes the combo of Evil Smile (whole party, causes Fear) and Ghastly Wail (anyone with Fear dies) a Total Party Kill unless you're really lucky. There are two Hope Spots to it, though; it can be used against enemies, and it wears off after a while.
 * Shadow Burn To Ashes for beginners. At this point, you only have three party members; one of which has a fire weakness. You can pick up a Slime that has Red Wall, which can seal said party member's weakness for 3 turns . . . but Slime itself is weak to fire, and the only healing spell you're likely to have at this point is Dia or Media. And since this is an ATLUS game, the AI will exploit any chance you give it to murder you.
 * On the same boss, the has an attack called Terror Voice, inflicting Fear upon you. It's not so bad on its own. The real kicker is when  follows up with Shivering Rondo, which does a HUGE amount of damage to anyone inflicted with said ailment.
 * Everything used by . His regular attack can deal out triple-digit damage, is unblockable, and is enough to kill anyone in two shots, which is a serious problem considering gets 2 turns. Then there's Bomb, which deals massive damage and can cause Exhaustion, which drains SP every turn. Lastly he has Gigadyne, which is as strong as his regular attack and it hits the whole party.
 * Shadow 's Roar of Wrath, which gives female characters the Rage status. While this could work in your favor (when enraged, people will attack enemies with boosted strength), the only two females in the party at the time are Chie and Yukiko. And Yukiko is the designated healer for the party. He also likes to follow this up with Tetrakarn, making those powerful attacks go right back at the girls. Have fun watching them get instantly killed for attacking ! This is also made potentially worse if you haven't killed off one of the flunkies that are healed by physical attacks.

Devil Survivor

 * Megidoladyne from . Deals enormous damage to everyone in every friendly party, and gets stronger the more times he uses it. 50% more powerful, to be exact. Once he Turns Red, he will use it every turn. will use it upon  and every turn afterward. And inevitably again upon . Since Megidoladyne becomes more powerful every time he uses it, it becomes an instant kill on the entire map after four-five uses. If the party is adequately overleveled. Which means that you have to beat  without letting him have more than two turns. Welcome to hell.
 * For reasons mentioned above, the fight with can become literally impossible, as he will be doing more damage in one attack than the maximum HP any member of your party is allowed to have, regardless of level, and is not capped on how often or how fast he can cast it.  is easily capable of casting Megidoladyne extremely rapidly in his third form at random, and even at maximum level with the best demons and skills possible equipped, making it so that no matter what you do to prepare, the fight with  has a real chance of being totally impossible to win after you've already beaten his first two forms. Welcome to hell, indeed.

Digital Devil Saga

 * Digital Devil Saga's Bonus Boss,, gives us "Gaea Rage." Deals around 7,000 points of damage to every character when your maximum HP is 999. Not to mention the only defense against it is very vague and requires luck to work. You'll have nightmares about it.
 * Being possibly the hardest boss in video game history, all of his attacks are pretty devastating. Javelin Rain hits everyone for decent damage and can inflict Stun while Xeros-Beat substitutes the (more devastating) Mute for Stun. Even his basic physical attacks are cringe-worthy, as not only do they hurt badly, but he has an ungodly high chance of getting a critical hit and getting an extra turn.
 * Adding insult to injury is having played Nocturne and realizing that Gaea Rage isn't even a particularly good attack. Apparently, he deems you unworthy of wasting Spiral Viper or Freikugel... or of bringing Dante as backup. He's generally not wrong about that.
 * There's also Vanity, the DDS equivalent of Bad Breath (see below).
 * Zotzilaha Bane, used by Camazotz. It turns one party member into a bat, giving them abysmal stats and a large weakness to Force. Three guesses what all of his elemental attacks are.

Shin Megami Tensei Nocturne

 * Matador's Red Capote maximizes his Hit/Evasion rates, making it nigh impossible to land an attack if you aren't prepared to counter it somehow.
 * Also, Andalucia, which hits the entire party several times. It doesn't do that much damage on its own, but is usually used after Focus, making the first hits very strong, or even worse Taunt, which puts a huge dent in your defense.
 * Ahriman's Apocalypse deals incredibly high unblockable damage. Pray that he doesn't use Megidolaon on the same turn.
 * If the True Final Boss ever decided to use High King or Root of Evil twice in a row, you were pretty much dead. Keeping your HP maxed every round was necessary to survive it, despite its low probability.
 * Dragon's Eye, turning one press turn into four halves.
 * Beast Eye, turning one into two halves. However, these halves can be turned into two more halves each. WHY?!?
 * Bael's Bane, which turns your ally into a fly. Can be blocked, at the cost of being weak to instant kill magic the boss uses (bar Crazy Preparation of course).
 * Death Flies: either you're immune to dark-type death or you...well, die. Otherwise you take heavy almighty damage.
 * Fire of Sinai: the random number generator god seems to enjoy having multiple hits of almighty on your main character.
 * Holy Melody if you're not careful. Yay, let's have the boss fully heal himself shall we?
 * Same goes for Evil Melody. Main character a bit lower on HP than other party members? HE DIES!
 * Anything used by Dante. Stinger hits one character for Almighty damage, and instantly kills anything on a Critical. Provoke is an enhanced version of Taunt, which drastically increases your attack but lowers your defense; Provoke does this and also HEALS DANTE. He also has an attack called Showtime, which deals a gigantic amount of Almighty damage to your party, and Bullet-Time, which hits your party for pretty good damage and causes Panic.
 * Red Rider's Terrorblade. It does huge damage and can randomly cause the Panic status. One of three things will happen when someone has this status (aside from nothing): They lose a turn, they throw away some money, or if it's a demon, they might run away. Granted, you can call them back, but that's only if the Demi-Fiend didn't get hit by it as well.
 * Sol Niger, used by Aciel, is an HP to One attack that hits the whole party. Bosses get two actions in one turn, and Aciel will invariably use that second action to attack one of your characters. If he hits the Demi-Fiend? You had better be used to that Game Over video.

Strange Journey

 * First off, anything that causes fear. Your demons may not do anything - or even retreat - and it can last multiple turns.
 * Asura Roga, used by (who else?) Asura . This causes Rage, which cannot be cured with anything but Amrita or Salvation (and you don't have the latter at this point). Rage is similar to Charm, with the minor difference that the victim can attack anything, Asura included - but the odds are much higher they'll attack the party.
 * Wave of Death, which deals ungodly damage. If Ouroboros uses it twice in a row, you lose.
 * Ouroboros also has another godawful attack: Disaster Cycle, which inflicts random status effects on everyone in the party. One unlucky turn where she hits the player character with Petrify or Bomb and you lose instantly. And in her second form, she spams it.
 * Any Almighty skill. You have no way to block them. (Neither do your enemies, but guess who'll face them more often?) Bonus points to Hostile Terror, this game's answer to Bad Breath (see below).
 * And finally healing ones: Tiamat,  would be WAY easier if they didn't have Pure Blue to fully heal them and cancel all debuffs. Only Tiamat gives a way to avoid it (do not reduce any of her stats to -4). Or  's Self-Denial, which heals and boosts attack, or that moment when he hits 0 hp and then regenerates 7500 spontaneously, giving a higher total HP than anything else in the game! This is a Nintendo Hard game, if not more so.
 * Speaking of, Adaptation. This is an attack he will only use on the main character, and the only way to survive it is to have full health, be on defense, and have something equipped to resist physical attacks. Even then, there's no guarantee this move won't flat-out kill you.
 * And, depending of the amount of money you happen to have at hand, you will want to kill yourself if a an irredeemably stupid enemy hits you with Macca Beam, or God forbid, Wastrel Beam. You lose, not a fixed amount, but a percentage of your total. You can lose hundreds of thousands of Macca to Kangiten's Wastrel Beam.
 * Anything that causes the Bomb status. If a Bombed character gets hit with even the weakest attack, they die and deal their HP in damage to the party. Gods help you if the unlucky target happens to be the main character.
 * 's Kiss, used by the Final Boss on the Law and Neutral paths. It hits 6 to 8 times for physical damage and can deal four-digit damage even with your defense capped. There is one way to negate it, but by using it, you make yourself vulnerable to the boss's One-Hit Kill moves. And she uses it a lot.
 * . Like Mitra's Light of Order, it is a guaranteed, unblockable instant kill of one character. This time, however, it CAN target the protagonist. I hope you know how to repair a DS.