NetHack

""While the graphics may seem primitive by today's standards, today's gameplay seems primitive by Nethack standards.""

- Christopher Wellons

NetHack is old. It began life in 1987 as an online version of Hack, and even now its development is still in progress.

NetHack is complex. It can take years of play to see it all.

NetHack is random. It is one of the three founding roguelikes and will sometimes generate levels that seem flatly impossible. But they never are.

NetHack has been described as a puzzle game hiding inside a roguelike's skin. Whereas the archetypal Angband or Dungeon Crawl hero is a knight in shining armour who slays countless evil creatures and becomes powerful like unto God, the archetypal NetHack hero is a cunning trickster (or... hacker) who sets traps, fights in unconventional ways and never, ever plays fair. After the very first few levels, killing monsters for XP becomes unprofitable (or even disadvantageous). Instead, power comes from your ever expanding collection of items which can be wielded, worn, thrown, rubbed, dipped, engraved, snapped, pointed, combined, cast, eaten, or applied, singularly or in combination.

The advantage of NetHack's focus on items is that it reduces the impact of luck. By carefully hoarding your resources, (almost) nothing is inescapably fatal. The downside of NetHack's focus on items is that it reduces the impact of luck. Once you've learned some effective tactics, multiple playthroughs can start to feel similar, or even repetitive.

Still, for a free game (in the sense of both "free speech" and "free beer") that can take up to a decade to beat for the first time, you could do worse.

NetHack is cross-platform; it's safe to bet that if you're using an operating system that's still being developed, there's a port for it. In fact, Linux distributions tend to feature ports of it in their software repositories, and anyone with the proper programming skills can make ports or modifications because it is free and open-source software, released under the terms of the NetHack General Public License.

You can also play it online here, at Hardfought, or on various other public servers - you can even use a telnet or SSH connection to connect and play from a compatible terminal. The latest released version is 3.6.6 and all entries apply to that version, although NetHack 3.7.0 is in rolling release Open Beta, meaning that it is available to play on Hardfought as it is being developed. You can find the main wiki here. A dedicated NetHack Reddit can be found here, and chatrooms for discussing the game itself can be found on freenode at #nethack and #hardfought.

If NetHack's rather archaic graphics intimidate you, you can always try Vulture, an isometric GUI that more or less takes the original and spits out detailed graphics, sounds, and all around allows for an easier experience when learning how to play. The official site is down, but there are forks; Vulture has builds for vanilla NetHack, SLASH'EM and UnNethack, with the Sporkhack variant coming soon. Additionally, the NetHack Wiki has a list of other alternate graphical tilesets.

Naturally, the NetHack General Public License means that there are multiple variants (the community term for forks) of the game, each with their own relatively unique flavoring; some branches, such as SporkHack and UnNetHack, arose in response to the belief that work on the official game had ceased. One highly recommended variant on the original game is DynaHack, which not only adds new content, but also includes an in-game tutorial and a friendlier user interface, which makes it perfect for beginners.

'''Important Note: Spoilers are easily accessible via the wiki and IRC, but there is always the difference between knowing of something and experiencing it for the first time - even so, in the spirit of being as new-player friendly as possible, spoiler tags are used on this page. The NetHack community defines "spoilers" as not just including plotline spoilers, but gameplay-related ones as well. The plot itself usually has far less direct impact on the game than its various mechanics, so if you wish to experience as much of the challenge as possible, read with caution and mind the spoiler tags and links.'''


 * The Dev Team Thinks of Everything: It even has its own page.
 * There's also the bugs list, for things the Dev Team didn't think of, though it becomes funny when you realize that most every bug listed seems to loop back around into examples. You can't rub a touchstone on gold? Why bother in the first place? Lit potion may survive hero dying from splattered oil burning on the floor... Who the heck noticed that?
 * Sunsword didn't work as expected against shades, although a player normally wouldn't run into shades until Gehennom, at which point they have far more viable weapons. Someone actually took the time to figure that out - and as of version 3.6.0, it's been fixed.
 * Random Number God: A term coined by the NetHack community, as noted in the "Deification" section of this article. The term originated from the "rgrn" Usenet newsgroup, with archives of the FAQ (formerly maintained by Dylan O'Donnell) going back as early as February 2002.
 * Yet Another Stupid Death: Also coined by the NetHack community during the Usenet days, often shortened to YASD. And best believe there are a lot of stupid ways to die. The wiki even has a list, imported from the IRC channel's bot!


 * Shoplift and Die: The trope was once named Izchak's Wrath, after the only non-random shopkeeper in NetHack.

"NetHack is a game, so you 1337 H4XX0RZ can just go... away."
 * Acronym and Abbreviation Overload: The IRC channel for NetHack often combines this with the in-game symbols used to represent the various items; so a late game ascension kit might contain (among other things) [oMR, "oLS, a cursed !oGL and plenty of /oD.
 * Acquired Poison Immunity: And many other types of immunities besides.
 * Action Bomb: Gas spores explode upon dying normally, which can easily kill low-level players, and spheres and lights attack by exploding at the player character.
 * Adam Smith Hates Your Guts: Can become this if you're hungry, have really low charisma, or are wearing a Hawaiian shirt.
 * A God Is You: For those, and also for the occasional attentive player who discovers that . The latter is unambiguously spelled out in the game's source code, but it's alluded to in a couple of other ways in the endgame sequence:
 * If you try tinning any of the corpses you get this message:
 * All There in the Manual: The in-game guide is a remarkable collection of quotes and information, not all of which is entirely accurate in describing game mechanics. There is also an encyclopedia that can be used to look up interesting quotes associated with certain monsters.
 * Ambiguous Syntax:
 * Amplifier Artifact: The Magic Mirror of Merlin exclusively gives Knights double damage to most of their spells in addition to its other intrinsics.
 * Anachronism Stew: Let's see... playable characters include an Indiana Jones-inspired Adventurer Archaeologist, a Conan the Barbarian-style Barbarian Hero, a caveman, a Samurai, and a Hawaiian-Shirted Tourist complete with a credit card (used to pick locks). Items and enemies include traditional staples like Dragons, Demons and Giants, but also included are things like Grid Bugs, Quantum Mechanics, and jabberwocks. Finally, plastic, while fairly uncommon, isn't unknown either.
 * And Your Reward Is Clothes: T-shirts, Hawaiian shirts and regular gloves are among the many types of armor you can encounter. Not that they're any less useful; enchanted shirts can provide a light and nifty source of extra AC, and this also holds true for gloves.
 * Anticlimax Boss:
 * The Valkyrie quest nemesis:
 * The Goblin King in the days when Elf was a character class.
 * The Rogue quest nemesis, especially compared to the quest levels before him. The most difficult part of defeating the nemesis is actually reaching him:
 * Prior to 3.6.1, Vlad was so anti-climatic that it had become a Running Gag to Cherry Tap him to death with -3 throughly corroded orcish daggers, thrown scrolls, and other such things, and name the object in question "Vladbane".
 * Anti-Frustration Features:
 * The renameable "fruit" (called "slime mold" by default) and various food rations are classified as vegan food, making vegan or vegetarian conduct much easier.
 * Anti-Magic: Magic resistance is a rare and valuable property that nullifies most of the damage and adverse effects from many magical sources, though it doesn't protect your inventory from them. It does, however, nullify rays and touches of death, and protects you from involuntary polymorphing via traps.
 * The cancellation spell and its wand equivalent can rob most monsters of their magic and some other special abilities, and turns most items into their mundane equivalents while removing blessing or curses from others.
 * Arbitrary Skepticism: The atheist conduct requires absolutely no interaction with religion or the gods whatsoever, despite them very definitely existing in-universe and the goal being Ironically, the Priest role is best suited for the conduct, since they start the game with holy water (an atheist Priest with holy water, try and figure that out) and have intrinsic knowledge of whether items are blessed or cursed without needing to use an altar.
 * Artifact of Death: Downplayed - artifacts can "blast" players that are not of the correct role or alignment for them, which can potentially instakill weaker characters.
 * Artifact Title: Most people nowadays probably won't know NetHack is an open source port of Hack developed on the then-new Internet unless you ask, to the point that newbie hackers on IRC have constantly mistaken the #nethack channel for an actual hacking forum for years! To quote the topic from #nethack on Freenode:
 * Artifact Title: Most people nowadays probably won't know NetHack is an open source port of Hack developed on the then-new Internet unless you ask, to the point that newbie hackers on IRC have constantly mistaken the #nethack channel for an actual hacking forum for years! To quote the topic from #nethack on Freenode:

"A gold naga hatchling wriggles out of your pack! Its cries sound like "Mama.""
 * Artistic License: Biology: Nutrition in NetHack is... strange to say the least if you try to compare it to real life. While drinking is entirely optional and Nobody Poops, you'll still have to eat regularly, and only overeating can cause you to choke (though it does abuse dexterity). Various other subtropes and examples include:
 * All Animals Are Dogs: Domestic animals can be tamed by throwing the appropriate food at them, and the only way to tame most other monsters is with a scroll of taming (or in some cases by wishing for a figurine). Among other things, tamed monsters will follow you around, attack other monsters they deem threats, and can even be put on a literal leash! Throwing food (especially treats) to an already-tamed monster will increase their tameness, as long as it's food they'll eat, and only tame pets have to worry about hunger.
 * Diurnal Nocturnal Animal: Monsters (including you) only sleep in special circumstances that aren't tied to the time of day - which the game does check, albeit for other reasons.
 * Misplaced Vegetation: You can find trees in most of the quest branches, which are usually outside... and also in the underground Minetown. Perhaps they were planted as decor?
 * More Predators Than Prey: Carnivores and omnivores make up most of the monster roster; in comparison, there are relatively few herbivores, and actual plants are rare, with most of the "plant" life being fungi. Among other things, it seriously cuts into the list of vegetarian-friendly food.
 * If an egg hatches while you're carrying it, the resulting young may be generated tame - the odds of it happening even depend on the gender of your character!


 * Ascend to a Higher Plane of Existence:
 * Attack Reflector: Granted via shield, amulet, or silver dragon scales/scale mail, and able to protect you and your inventory from the effects of magical rays while deflecting them back in the opposite direction.
 * Auto Revive:
 * And it doesn't do much to remove the source of the death, either...
 * Awesome but Impractical: Crystal plate mail is among the highest AC armor in the game and doesn't interfere with spellcasting - but it's also incredibly heavy AND somehow fragile enough to break if thrown or dropped from a sufficient distance.
 * Bag of Holding: Appears as an item that reduces the weight of its contents when non-cursed.
 * Baleful Polymorph: Stepping on polymorph traps will change yours or a monster's form instantly unless they have magic resistance or a means of polymorph control - and the victim is very likely to drop or tear through some of their armor in the process. Polymorph rings are often generated cursed so as to inflict this on unsuspecting wearers, and zapping wands of polymorph can inflict this on enemies (and yourself).
 * Sliming can occur as a result of a green slime's attack, and will eventually turn you into a slime yourself, ending your game unless it's cured.

""Thou hadst best fight better than thou canst dress!" "Twixt thy cousin and thee, Medusa is the prettier." "I first mistook thee for a statue, when I regarded thy head of stone.""
 * Bandit Mook: Leprechauns and nymphs can steal gold and items from you respectively, and teleport away after a successful steal, making retrieval fairly annoying at best. "Covetous" monsters can attempt to steal certain items such as quest artifacts from you.
 * Bare-Fisted Monk: Despite not being able to effectively use weapons, monk characters can become extremely powerful and deadly. Various other roles can also train their bare-handed fighting skills (or martial arts for monks and samurai), and the weaponless conduct centers around fighting without wielding traditional weapons.
 * Bear Trap: Appears as one of the many traps, and tripping one damages the victim and holds them in place for a while or until they're freed.
 * Big Red Devil: The horned and barbed varieties appear in Gehennom as Mooks.
 * Blindfolded Vision: Invoked with intrinsic telepathy, which is heavily desired by zen players. It's also possible with extrinsic telepathy, and is an option to protect against gaze attacks.
 * Blinding Camera Flash: Expensive cameras can be found, and their purpose is to blind and scare monsters with the flash.
 * Block Puzzle: Sokoban, a four-level puzzle in which you push boulders to plug holes in the floor. The game mechanics change somewhat, though: You can't push the boulders diagonally or fly over the holes in the floor, and destroying the boulders (or creating more) nets you a Luck penalty.
 * Bolt of Divine Retribution: Tick off your god enough, and you'll get struck by lightning.
 * If you manage to
 * Boss in Mook Clothing: Liches. They can curse your items and lower your strength, their cold touch can destroy potions in your open inventory, and the stronger ones can even use a Touch of Death!
 * Archons, titans and ki-rin are devastatingly powerful foes that appear very rarely in the dungeon. On average (i.e. barring shapeshifter shenanigans) you'll only ever see them late in the game, at which point you'll understand just why that is - they're nasty summoners, can curse your inventory and even death-touch you in some cases, and each has their own ability that can cause you no end of trouble, be it the archon's dazzling gaze, the kirin and archon's ability to fly, or the titan's Super Strength.
 * Bottomless Bladder: The PC isn't required to sleep, and recovers from wounds without having to rest. In fact, the only source of restful sleep is delivered by an amulet of restful sleep, which can be used to heal, but is mostly just there as a hazard.
 * SLASH'EM subverts this with the addition of toilets, but their use isn't obvious at first. If you're satiated and sit on one, you "take a dump" and lose some nutrition, along with being cured of sickness, stunning and confusion.
 * Breakable Weapons: A variant - you cannot break melee weapons through fighting with them, but using bladed weapons to force locks can break them. Missile weapons such as darts, arrows, and slung rocks have a chance of breaking when thrown.
 * Katana wielded by samurai and two-handed weapons have a 5% chance of shattering an enemy's wielded weapon and causing them to flee.
 * Cap: Several things are capped in NetHack.
 * The player's ability scores are capped at 25 (after all bonuses are applied).
 * The highest possible Luck score is 14 (13 if it isn't a full moon).
 * The player's experience level is capped at 30.
 * Monster hit dice (for "normal" monsters) are capped at 49.
 * There are quite a few things that aren't directly capped, allowing them to go as high as 2^8-1, 2^16-1, 2^31-1, or possibly even 2^63-1 depending on the size of the variable they're stored in.
 * Cheap Gold Coins: A fortune cookie costs 7 gold zorkmids, a food ration 45 zorkmids, and artifact weapons cost a few thousand zorkmids. Back-calculation from the weight system suggests that a zorkmid weighs about 40 grams, or about one and a quarter troy ounces. In the last 10 years, Real Life gold has varied between approximately $200 and $2000 per troy ounce, so that's $1,750-$17,500 for the fortune cookie, $11,250-$112,500 for the food ration, and a cool million or ten for something like.
 * Cherry Tapping: Typically "Vladsbane", named for one boss that was formerly so wimpy, he could be dispatched with a rusted tin opener or thrown magic marker.
 * Chess Motifs: Knights have the intrinsic ability to jump to other squares in the same way as the knight chess piece, and unicorn will attempt to keep a knight's jump away from players. Neither can jump through or over other objects, though.
 * Chest Monster: Mimics lurking in stores, where they sometimes disguise as chest-like objects, are common killers of low-level characters.
 * Color Coded for Your Convenience: Unicorns are color-coded by alignment (black/chaotic, grey/neutral, white/lawful). Many other monsters, particularly dragons, are coded by properties: monsters with fire attacks (pyrolisks, hell hounds, red dragons) are usually red, monsters with cold attacks (blue jellies, winter wolves, white dragons) are usually blue or white, etc.
 * Combinatorial Explosion: Sometimes literally. But no matter how funny it would be, never ever . For that matter, don't either.
 * Commonplace Rare: Two of the most useful items in the game are... the magic marker and the can of grease. Both are disgustingly uncommon. Grease is mostly valuable because it is rare—its ability to protect your armor from damage is important, but mostly superseded. Magic markers, however, let you write powerful and valuable magic scrolls on junk parchment (and are used up in the process), making them quite desirable.
 * Another inexplicably uncommon item: shirts. T-shirts and Hawaiian shirts have no armor value in and of themselves, but can be enchanted to give a valuable extra few points of protection. If you can find one. Wishing or polymorphing may be necessary.
 * Conservation of Ninjutsu: Oh, you wish. Letting monsters gang up on you is a quick way to end up dead.
 * Contractual Boss Immunity: Played with. Most quest nemeses are immune to stoning, but otherwise their immunities tend to vary, and many can be felled with poisoned weapons or even wands of death.
 * Taken Up to Eleven with the Chromatic Dragon, who has resistance to almost every element and form of magic - and reflection!
 * Convection, Schmonvection: Mostly subverted. You can stand next to lava with no ill effects, but if you try even flying over it without fire resistance you're in for a world of pain. Water Walking boots will let you walk over lava, but if they aren't fireproof themselves the lava will destroy them, leaving you to fall in and die as a result.
 * Crazy Prepared: The player must be this if they want so much as a chance at winning.
 * Critical Existence Failure: Down to one HP? Go ahead and kick a wall. I dare you.
 * Damage Discrimination: Averted; if you're facing a mob of enemies, anyone between your character and a missile-user (up to and including dragons) stands a chance of getting hit. Also, if you wear a ring of conflict, any nearby creatures will start attacking each other.
 * Danger Sense: The warning ability, available via intrinsic and extrinsic, highlights the location of nearby monsters with a number based on how dangerous said monster is. The searching intrinsic tcan also function as this to a degree, as it can automatically pick up on trap locations before the player steps on them.
 * Deader Than Dead: That Auto Revive up there? It doesn't work if you Well, technically it does, but you just die again.
 * Death by Sex: If you're not careful when you initiate an encounter with a foocubus, you may suffer such stupid deaths as: turning to stone because ;
 * Debug Mode: Or "wizard mode", rather. Useful for demonstrating and clarifying the results of certain interactions on a live basis that you wouldn't be able to (reasonably) explore in a normal game.
 * Demon Lords and Archdevils: Asmodeus, Baalzebub, Juiblex, Orcus, and many others await you in Gehennom.
 * Depleted Phlebotinum Shells: Garlic appears as an item, and there are various silver weapons and items that do extra damage if used against demons, vampires and werewolves.
 * Detect Evil: Some artifacts can warn the player of particular types of hostiles.
 * Deus Sex Machina: With proper preparation (or, as many like to say, "protection"), seducing succubi and incubi can permanently raise your level or stats and is generally a great resource.
 * Diagonal Speed Boost: Naturally, as it's a roguelike. The "grid bug conduct" challenge is for your player to ignore the speed boost, which makes the game a lot harder.
 * Disc One Nuke: In quite a few ways, be it an early wish or polymorphing.
 * Some players regard "Elbereth" as this. Writing Elbereth in the dust with just their fingers can protect the player from almost all early monsters and many later ones. In 3.6.0 on, it was significantly nerfed to the point of causing another break in the base.
 * Due to starting skill levels, a Rogue on the very first turn can throw up to 2 daggers at a time. Developing the skill can increase that to up to 4 daggers at a time. Enchanting the daggers (or finding enchanted daggers), plus strength damage bonus, means a Rogue is almost guaranteed to be a long range killer by machine-gunning daggers; this is why Rogues start with a stack of daggers. Rangers can do the same, but have to find the daggers on their own, as well as develop the skill completely from scratch.
 * Charm monster is an invaluable spell for Tourists or Wizards... if you can find the book and have the right armor to cast it reliably. Once you do, it can prove an absolute lifesaver, as not only can you obtain powerful pets such as the people-eating purple worms, but you can also use it to deter especially menacing attackers, such as minotaurs or a freshly-summoned swarm of nasties.
 * Do Not Drop Your Weapon: Averted; you can unequip enemies with a bullwhip, though enemies can do the same. Weapons can also be stolen liek other items - if Magicbane is your only source of Magic Resistance, and you're disarmed while somebody with a touch of death is around....
 * Eating greasy food can cause the player's weapon and anything else they wield to drop from their hands, and can only be remedied by waiting a few turns or using a towel.
 * Do Not Pass Go: The game displays the message "Do not pass go. Do not collect 200 zorkmids." if you die on your first turn.
 * Dracula: One of the many bosses.
 * Dual-Wielding: Blessed +7 Grayswandir and a blessed +7 silver saber, yeah baby!
 * Dummied Out: 'Deferred features' include the shimmering dragon and vorpal jabberwock, as well as unique characters like Cerberus and Charon. There was also planned to be an artifact attack that fired magic missiles (similar to Fire and Frost Brand's secondary effects) and spellbooks that could summon spheres.
 * Dungeon Bypass: Pick-axes can be used to tunnel around enemies and to dig a hole through the floor of one dungeon level down to the next, letting you bypass entire levels at a time (although you will have to deal with the bypassed levels on the way back up—unless you've got another cunning plan).
 * Dungeon Shop: An important source of items, and (possibly even more importantly) clues as to what the items are - their appearance is randomized for each game and use-testing can be a very Bad Idea.
 * Early Game Hell: Depending on the role, but especially if you're new and playing unspoiled. And yes, this applies without potential "gnome with the wand of death" scenarios.
 * Easter Egg: Too many to list. Most actually overlap with The Dev Team Thinks of Everything in that the player is trying to do something strange, but the game gives an appropriate response instead of simply giving a generic 'you-can't-do-this' response.
 * "You pick up the trapper's tongue. But it's kind of slimy, so you put it back down."
 * "That would be an interesting topological exercise."
 * Eat the Dog: You can eat domestic cat and dog corpses, though doing so is a Very Bad Idea™ unless you're an orc.
 * Elemental Embodiment: Earth, fire, air and water elementals show up as dungeon inhabitants and enemies; they can also be summoned by other means, much to the chagrin of anyone messing around with sinks or fountains.
 * Elite Mook: Many monsters have "lord" and "king" variants, alongside other general "upgraded" forms, and it's possible for them to level up into these forms.
 * Enemy Summoner: Werecreatures can call monsters within their animal's class for help, and many high-level spellcasters (including several quest nemeses) can summon strong monsters to surround you when casting in melee range. Demons are also capable of "gating" in more of their kind when attacking in melee.
 * Any monster can technically become this if they get their hands on a wand or scroll of create monster.
 * Everyone Has Standards: The dungeon's hostile inhabitants will become aware of your presence far quicker if you have the "aggravate monster" quality, which you can get intrinsically by eating domestic cats and dogs or committing cannibalism (unless you're an orc in either case or a Caveman in the latter case).
 * Everything's Better with Samurai: Not only can anyone get a katana, but a bunch of items are renamed in Japanese if you play as the Samurai role.
 * Everything Trying to Kill You: Oh are they ever.
 * Even Evil Has Standards: The Random Number God may occasionally give a gnome a wand of death, but at least it draws the line at letting monsters use scrolls of genocide.
 * Evil Army: The Wizard of Yendor has command over one, as well as other bosses like Croesus.
 * An army of orcs may pillage Minetown and leave it in ruins; in a game with "Orc Town", you can find named orcish monsters with various items and loot that would normally appear in the town, up to and including the captain, spread throughout the Mines and the rest of the dungeon.
 * Evil-Detecting Dog: Any non-undead pet has the innate ability to detect cursed items, and will try its best never to step on them, or to do so only "reluctantly". Also, when leashed, they will whine or act nervous whenever there's a trap nearby.
 * Evil Has a Bad Sense of Humor: Most hostile demons will frequently utter maledictions when battling you, such as the following gems:
 * Evil-Detecting Dog: Any non-undead pet has the innate ability to detect cursed items, and will try its best never to step on them, or to do so only "reluctantly". Also, when leashed, they will whine or act nervous whenever there's a trap nearby.
 * Evil Has a Bad Sense of Humor: Most hostile demons will frequently utter maledictions when battling you, such as the following gems:


 * Evil Tower of Ominousness: Both Vlad and the Wizard can be found in one; the "fake" Wizard's Towers are designed after Rodney's old dwelling from the earliest versions.
 * Fair Weather Mentor: The player, almost inevitably. You'll love your pet and give them easy kills and fresh corpses to help level them up, and they'll fight on your behalf... but when food starts getting scarce or you find yourself cornered by a level-draining foe, it's every man for himself. There's no penalty for starving your pets to death or abandoning them when the going gets tough except the loss of the pet. Just don't Eat the Dog unless you really have to.
 * Fake Difficulty: Despite NetHack's awesomeness, it is hard not to admit that the game definitely has a share of it. Namely:
 * Trial and Error Gameplay. Described below in detail.
 * Guide Dang It: It would be difficult-shading-into-impossible to win without reading spoilers on some of NetHack's more arcane mechanics. Like all good things, they have their own wiki. Some of the variants, including SLASH and SLASH'EM, assume you have memorized the guide and up the difficulty to match.
 * Selective Memory: The game provides almost no useful information about how various spells and items work, what dangers some special monsters present, etc. But how come? Does your character know absolutely nothing about Mazes of Menace? Even if so, why do they know nothing about items they bring with them? Sure, their types and blessed/cursed status is revealed, but no information is provided about how they actually work.
 * The Random Number God. If he gets angry, you are screwed. Experienced players have demonstrated that most games are winnable, but you also have to be a very experienced player to truly "appreciate" it.
 * Filk Song: Filk singer Rob Balder wrote a song about the game. You can listen to one version of it here.
 * Final Death: All deaths are final, unless you have a certain rare item...
 * Fire and Brimstone Hell: The Valley of the Dead and Gehennom.
 * Foe-Tossing Charge: The game has many instances when the player is surrounded by monsters and only needs to pass through; the easier way to do this (or something resembling this) is zapping a wand of teleport through the horde, or else breaking a spare one in two and teleporting anything within range.
 * In games where mail is enabled, the Mailer Daemon (yes, an actual demon) will do this in order to get to the player and deliver their message if necessary.
 * Forgot to Feed the Monster: While food is very common and you usually don't have to actively feed your pet(s), it is possible for them to starve to death. This can annoyingly be reversed if you're hungry, but your pet gets to edible food before you can. Your pet(s) will also go feral if you leave them on a different level for too long, and can end up attacking you while confused from hunger.
 * Fourth Wall Mail Slot: On some Unix systems, if you receive a new email while playing, the email is brought to you on a scroll in-game, delivered by the mail daemon.
 * Frankenstein's Monster: Flesh golems are modeled after him - they resist shock damage and are healed by it, and their encyclopedia entry directly quotes Mary Shelley's Frankenstein.
 * Friendly Fireproof: Averted. Ranged attacks from any source can hit anything in the line of fire, including other peaceful or hostile monsters.
 * From Nobody to Nightmare: Vlad the Impaler in 3.6.1 - he went from the butt of every player's jokes to the second-fastest monster in the game and a level-draining menace.
 * Fun with Acronyms: The fandom has multiple acronyms just for the act of dying, with varying levels of unfairness implied: YASD (Yet Another Stupid Death) is in regard to deaths that were your fault, YAAD (Yet Another Annoying Death) is in regards to deaths that were beyond your control i.e. instadeath attacks, DYWYPI (Do You Want Your Possessions Identified?) which is sighed by many a player on the freenode.irc channel after their death, and GwtWOD (The Gnome with the Wand of Death) which is a disappointingly common cause of YAAD.
 * The archived Usenet newsgroup FAQ is a good source of these and many more such acronyms that are still in use.
 * Game Mod: The NetHack General Public License encourages the creation of variants and other similar additions, which the community has produced many of.
 * Gender Bender: Possible through polymorphing or with amulets of change.
 * Genie in a Bottle: In magic lamps, as well as actual bottles. Possible source of a wish, if handled correctly.
 * Get Back Here Boss: Quest nemeses, end-game bosses and other powerful enemies can warp around at will, and will use this ability to run off and heal.
 * Golem: Various types serve as enemies; they are notable for being impossible to genocide, and can result from polymorphing piles of like items.
 * Gone Horribly Right: With work, it's possible to genocide a whole range of weaker creatures. Overdo the blessed scrolls of genocide and all that's left are the very toughest creatures, which aren't genocidable. The final stages of the game become even more exciting, and frequently, much shorter, too.
 * Good Is Not Nice: Oh, Archons are plenty nice if you're lawful, but if you're not or else anger one, you'll regret it.
 * Gratuitous Japanese: When playing a samurai, the game feedback will call certain items by their Japanese name (helmet -> kabuto) or a rough Japanese equivalent (booze -> sake), though they're the same item behind the scenes. The Samurai Quest is particularly full of this.
 * Grave Humor: Any grave that wasn't generated by a player's death randomly generates a humorous message. nethack.alt.org added a ton of them.
 * Grave Robbing: Can be done to find gold and items, though you may also unearth mummies and zombies. Samurai and Archaeologists suffer alignment penalties if they engage in this.
 * Hailfire Peaks: The Valkyrie Quest has both lava and ice on the same map, explained as the result of fire giants invading the naturally frosty Valkyrie homeland.
 * Have a Nice Death: Your tombstone tells you how you died; usually that just means which monster, but sometimes, it's much more unique.
 * For those who don't know where to look for the cause of death... he died by kicking a wall.
 * Sometimes, figuring out just how to reproduce a specific death can be a non-trivial exercise in itself. ("turned to slime by a scroll of genocide", anyone?)
 * It's even possible to have 'elementary chemistry' as a cause of death, if you're careless with acid.
 * Hawaiian-Shirted Tourist: All Tourists start with a Hawaiian shirt, not to mention an expensive camera.
 * Highly-Visible Ninja: Ninjas only appear on the Samurai quest, and aren't intrinsically capable of most the usual tricks associated with ninja. They do come with some of the Stock Ninja Weaponry, though.
 * Hoist by His Own Petard: The easiest way to kill is with.
 * Holiday Mode: Date, time, and phase of the moon may all affect the game.
 * On Friday the 13th, the start-up message says "Watch out! Bad things can happen on Friday the 13th", and your Luck stat is reduced.
 * On a full moon, the start-up message says, "You are lucky! Full moon tonight", and your luck is increased, but dogs may be less friendly, and werecreatures are usually in animal form, especially at night.
 * During the new moon, cockatrices are more dangerous.
 * Between 10pm and 6am, some creatures are slightly more dangerous.
 * From midnight till 1am, undead do twice as much damage, and you get a different message when entering graveyards.
 * Hollywood Acid: Averted in that most acid attacks only cause a few hit points of damage, and corrode metal items instead of instantly dissolving them.
 * Horny Devils: Foocubi (the gender-neutral name used for the succubus and incubus) can seduce the character (or just about anything of the opposite sex, including a dragon steed), cause a random effect (positive or negative depending on stats and chance) and teleport away.
 * Horsemen of the Apocalypse:
 * Human Sacrifice: Same-race sacrifice is possible, but highly unadvisable unless you're chaotic.
 * I Fought the Law and the Law Won: Keystone Kops spawn in large numbers if you rob a store, even by accident. They are among the only monsters in the game that can never be rendered permanently extinct; no matter how many armies of them you defeat, there'll always be another pack ready to jump you NEXT time you step outta line.
 * Implacable Man: Subverted; even when you're high level and well-tooled for melee with AC well in the negatives and a ring of regeneration, and you can smite an entire room of trolls and dragons, taking blows and regenerating the damage faster than they can dish it out, you can still get absolutely destroyed without the proper resistances, and in some cases even with them!
 * Improvised Weapon: You can wield nearly any item and use it for the blunt-force trauma if nothing else.
 * Infinity+1 Sword: Grayswandir, a silver saber which deals double damage to all monsters (instead of just extra damage like other artifacts) plus extra damage to silver-hating monsters, is widely considered the best artifact in the game, to the point that even non-Lawfuls may choose to wish for it in the late game.
 * Ranged attacks that make use of a weapon at skilled level or better can kill enemies before they even get withing melee range, and is typically called "storm" damage.
 * Cone of cold and fireball cast at skilled or better level can created repeated area-of-effect explosions that rack up tons of damage.
 * I'm a Humanitarian: Eating your own race is possible, but in most scenarios it's also a Very Bad Idea™.
 * Interface Screw: The Rogue level, a Shout-Out to the GUI of NetHack's predecessor, can be confusing to navigate if you're new or used to playing with tilesets.
 * Some of the Standard Status Effects can prove horrendous. When confused or stunned, moving takes you in the wrong direction most of the time; when hallucinating, you can't tell friend from foe. When blinded, you can't see anything, and unless you have a means of telepathy, you risk bumping into or touching something that may turn lethal in short order. Better not get blinded in shops and towns!
 * Inventory Management Puzzle: You can carry a lot of swag with the right items, but eventually you'll have to start caching; to be as certain as possible of not losing a cache, you can or
 * If it's not a permanent Elbereth, peaceful monsters can wander across it and scuff it out. Then the gelatinous cube shows up...
 * For sufficiently advanced players, most of the difficulty (and/or tedium) will come from this.
 * Invisibility: Available via both a cloak and a ring, as well as intrinsic invisibility conferred by wand (permanent), potion or spell (temporary). Note that it doesn't make you completely undetectable; monsters will try to guess your location and attack where they think you are. All of the above items can also be used by monsters, making the "see invisible" intrinsic very important.
 * Invisible Monster: The stalker is naturally invisible at all times, and can provide a source of invisibility and the ability to see other invisible beings.
 * Just Add Water: Several types.
 * Alchemy can be used to mix less-useful potions and generate more-useful potions.
 * Once you know a scroll or spellbook, you can write more copies with a magic marker on a blank scroll or spellbook. On the other hand, magic markers are hard to come by and often have to be wished for.
 * Katanas Are Just Better: They use the same skill as the long sword, but have slightly higher damage against small monsters and are +1 to hit.
 * Ki Attacks: The Monk gets these in SLASH'EM.
 * Kick the Dog: You can do this if you like, literally even. You Bastard. Seeing as your pet is your loving sidekick and one of your more useful assets, this is usually an accident when it happens.
 * King Mook: Gnome kings, dwarf kings, ogre king, Elvenkings, and queen bees.
 * Kitchen Sink Included: With a surprisingly large number of gameplay uses.
 * Leaning on the Fourth Wall: Applying a stethoscope to listen to the very bottom of the screen gives the message "You hear a faint typing noise."
 * Let's You and Him Fight: Invoked with the ring of conflict, which when worn causes every nearby monster that isn't you to start attacking any other nearby monster - including you! The Scepter of Might can also be literally invoked to generate conflict.
 * Level Grinding: The "pudding farming" method allowed you to collect massive amounts of hit points, as well as really good loot, at the cost of turning a lot of the game into a tedious slog, to the point that prior to 3.6.0, a player joked that the Dev Team didn't need to invent a punishment for pudding farming because there already was one—
 * Anti-Grinding: Leveling up too much before you find good equipment is a good way to get yourself into trouble.
 * Level Scaling: The level of enemies you'll face is based on the average of your character level and the depth you've reached in the dungeon.
 * Logical Weakness: Tridents do additional damage to aquatic monsters. Axes do extra damage to wood golems. Clay golems can be destroyed in one shot if you've read the original folk tale and . The list goes on...
 * Luck-Based Mission: Luck (both in the sense of the stat and RNG) plays an important role in NetHack; if the Random Number God wants to kill you, it probably will, because, at any given moment, there are many things that can go wrong. Taking precautions that will let you survive its wrath is an important part of the game.
 * Christian Bressler, aka 'Marvin the Paranoid Android', ascended 23 times in a row over a three month span on the public server NAO, mostly to show that any individual game could be won. Including one of every class for the first 13, prior to doing conducts.
 * Adeon, another NAO player, ascended 29 times in a row over the course of just barely more than one month.
 * One of the various traps that an adventurer can encounter is a pit. Sometimes, this pit has spikes. Sometimes, these spikes are poisoned. And sometimes, poison is instantly lethal. Therefore, characters who don't possess poison resistance could theoretically die at any given moment, should they wander into a trap such as this; the truly paranoid will try to only step where they've seen other monsters step safely, or search when that's not possible.
 * MacGuffin: The Amulet of Yendor is the primary one, and each role also has a quest artifact specific to them, guarded by their quest nemesis.
 * Macrogame: Bones files—a good argument for playing on an online server.
 * Magic Missile: One of the many spells available in the game, and can become ridiculously powerful due to scaling with your level.
 * Magic Pants: Subverted - if you change into a much larger form, then the armor you're wearing will be torn apart and destroyed. If you turn into something exceptionally weak and puny, you'll be half-squashed by the same armor and find it harder if not impossible to move.
 * Despite the amount of slots available, there are no mention of pants in the game whatsoever. If you sit on a cockatrice corpse, however, you don't turn to stone, so you must be wearing pants. Since they don't tear apart or anything, they must be magic. So the pants are magic, but it's averted with the rest of your clothing.
 * Magikarp Power/Lethal Joke Character: Arguably, all the "weak" character classes have this to some extent - but it's most noticeable with the Tourist, who might (arguably) be the easiest role to win with if you survive past the Quest. But that's a big "if." The Analysis page goes more in-depth.
 * Throwing darts are sufficient for most roles as a ranged attack, even if they lack the related skill; there are also plenty of dart traps to un-trap for more darts.
 * Mailer Daemon: A literal one - it delivers messages from other users when playing on a server. The daemon normally appears and disappears within one turn without giving a chance for the player to interact with it. However, a Crazy Prepared player can kill it, rendering it extinct and preventing further messages from being delivered; to do this, the player needs to
 * Make a Wish: The most certain, and in some cases only, way of getting some desirable rare items. On the other hand, it may be much more useful to wish for an item with an important Mundane Utility.
 * The Many Deaths of You: There are many (many, many) ways to die, leading to a lot of Trial and Error Gameplay. Some can only realistically be obtained by deliberately setting out to collect them.
 * Medusa: Appears as a boss on her own unique level, with some elements such as a statue of Perseus that allude to her myth.
 * Metagame: Many sort-of-intentional deaths are caused on the first few levels by people repeatedly seeking some early advantage, such as quaffing from fountains (it’s supplication to the Random Number God for a wish, in case you’re curious), or kicking sinks for a ring and then dying if a foocubus or black pudding comes up and they can’t handle it (or don’t want to waste time handling it). This is a form of startscumming, and not everyone thinks it's a-OK.
 * Mighty Glacier: Mumakil and baluchitheria.
 * Minigame Zone:
 * The Sokoban branch. Interestingly, the Mini Game is done with the same mechanics as the rest of the game, with only minimal changes to Sokoban's mechanics itself; boulders can't be pushed diagonally, you can't fly over holes in the floor, and certain other things (e.g. using spells to get rid of boulders) will give you a luck penalty.
 * One way to enter the Castle is by winning a game of Master Mind.
 * In the endgame,
 * Mission from God: The Excuse Plot.
 * Money for Nothing: There are things that are worth spending gold on, but the fact that you can kill almost anything you gave your gold to means that generally, once you're done with getting your protection and items, you're more or less done with money as well.
 * Monsters Everywhere: Horses, bees, trolls, elves, snakes, demons - and everything in between - grows out of rock. Or perhaps they are spawned by the evil Wizard.
 * But why then does he spawn a puny rat to defeat the hero that just killed five dragons without breaking a sweat? Maybe to maintain a certain ambiance? Kitten and vampire lord, fighting side by side!
 * Mook Bouncer: The quantum mechanic has a "teleport" attack, which is based on its Punny Name along with many of its other elements, and sends you to a random spot on the same floor.
 * Mounted Combat: Possible with many roles as long as you have a saddle and a compatible steed to apply it to.
 * Multi-Armed and Dangerous: Mariliths - while they can't wield more than two weapons, they get several claw attacks per turn.
 * Multiple Head Case: Ettins are two-headed relatives to giants that get two attacks instead of one, and can ignore player stealth a majority of the time.
 * Mundane Utility:
 * Basic leather gloves do nothing for you besides covering your hands and providing extra AC.
 * Simple sacks let you carry objects within them, which can also protect them from some types of damage and allows you to carry more than the 52-character limit.
 * Mushroom Samba: The hallucination effect can be obtained by drinking a certain type of potion, eating the corpses of some monsters (including several fungui), and being hit by an exploding (and usually invisible) black light. This causes nearby monsters and items to appear as random other items or monsters that don't actually exist, and also gives alternate messages for some other effects.
 * Needle in a Stack of Needles: One of the things the Wizard of Yendor can do to make your life more difficult is steal the Amulet of Yendor. And then leave fake ones. Do not try to enter the endgame without the real one...
 * Quaffing a cursed potion of gain level on dungeon level 1 is a failsafe way to exit the Dungeons of Doom.
 * Nerf Arm: Cream pies are surprisingly useful as weapons, and you can eat them.
 * Never Found the Body: Some monsters are programmed to never leaves corpses.
 * Nintendo Hard: To the point where there is no shame in dying on the second or third level if you're a new player. One can die in less than 50 turns if they don't know what they're doing, and it's not unheard of for players to die on their first turn.
 * Nobody Poops: No matter how much meat you or your pet consume, you'll never feel unpleasantly "backed up" (though you do risk choking), and there's no toilets in the dungeon anyway. Although there are sinks. See also Bottomless Bladder above.
 * Non-Human Undead: Zombie and mummy giants, elves, dwarves, orcs, and gnomes along with the regular ol' human variant. You can also zap most corpses with wands of undead turning to bring monsters and animals back to life.
 * No Ontological Inertia: Once you clear a Sokoban level, the movement restrictions regarding boulders are lifted, as are the penalties for breaking boulders.
 * No Ontological Inertia: Once you clear a Sokoban level, the movement restrictions regarding boulders are lifted, as are the penalties for breaking boulders.


 * Nostalgia Level: The Rogue level, a reference to the original "Roguelike", is presented in black and white, with different symbols for various features and objects, and even some changes to game mechanics (such as monsters not leaving corpses).
 * The Nudifier: Any piece of armor can be destroyed via the scroll of destroy armor and the 'destroy armor' spell used by certain monsters.
 * Olympus Mons: Figurines, the spell of charm monster and the scroll of taming make this possible. A high-ranking angelic being and an uber-powerful undead mage can both be your pets, despite possibly being powerful enough to destroy your character several times over. With a bit of work, even can be brought under your control.
 * One-Hit Kill: Tons of 'em, on both sides.
 * A wand of death, the finger of death, a bad roll on a poison check with no resistance, anything involving your bare skin and anything even tangentially related to a footrice or their eggs, Medusa's gaze...
 * Other situations can be "effective" one-hit kills, such as hitting a floating eye (which leaves you paralyzed and helpless for several turns, meaning anything can get free shots at you) or encountering anything from a soldier ant (Go Team a!) to monsters like the leocrotta, mumak and minotaurs when completely unprepared for melee.
 * Drowning attacks are technically a two-hit kill, but feel like a one-hit kill; if a monster is already securely wrapped around you near water and lands the attack again, it instantly pulls you in and drowns you.
 * Optional Sexual Encounter: Succubi and incubi - the page image for that trope is from this game.
 * Orcus on His Throne: Various monsters such as King Mooks and Croesus can be found "asleep" on thrones in special throne rooms. The Trope Namer himself appears, but is an exception to the rule.
 * Our Ghosts Are Different: Ghosts occur in graveyards and abandoned temples, and in most cases where a player's death leaves a bones file, you can potentially find their ghost near their belongings - along with any pets they have and, in most cases, whatever killed them. While ghosts themselves are not all that damaging, they can prove very hard to hit.
 * Our Giants Are Bigger: Giants can't wear body armor, but can still use other armor and weapons, and their strength lets them carry boulders with ease.
 * Our Trolls Are Different: They come with enhanced Regenerating Health and Resurrective Immortality that lets them come back to life as long as any part of their corpse remains. They also tend to generate with polearms.
 * Our Werebeasts Are Different: Werewolves, wererats, and werejackals.
 * Pet Interface: There's a surprising amount of mechanics and options for taming monsters:
 * The safe_pet and highlight pet options.
 * Carrying pet treats in open inventory (e.g. tripe for dogs/cats, pears/apples for horses) means your pet will stay much closer to you. Tossing your pet a treat reinforces its recent behavior. You can train your pet to steal from shops!
 * A leash physically keeps your pet close to you, even when going up/down stairs or dropping through holes. (You can use multiple leashes, too.)
 * A tin whistle will call your pet's attention to you. A magic whistle will teleport your pet(s) to your side from anywhere on the level.
 * #chatting to your pet can tell you about their condition.
 * Pets are reluctant to step on a square with a cursed item on it (unless there's food there they want). This can identify cursed items, and can also be used to control their movement.
 * You can apply a bullwhip at a humanoid pet to take their weapon, then leave a better weapon for them to replace it with. You can also prepare and leave weapons, armor, and tools for your humanoid pets to pick up and use.
 * A wand of probing tells what a monster (tame or otherwise) is carrying; a stethoscope displays a monster's basic Hit Points and its speed.
 * Spells of healing and extra healing can be used to heal pets, as can breaking a potion of regular, extra, or full healing on them.
 * Saddles permit horses, dragons, and some other monsters to be ridden.
 * Pinball Projectiles: Rays from spells and wands can be bounced off walls to hit tricky targets. They might also bounce back at you.
 * Portal Door: You're guaranteed to encounter at least a few of them, including the one leading to your quest.
 * Press Start to Game Over: If you're very unlucky with the Randomly Generated Levels, or else going out of your way, it's possible to die on your first turn, and there's even a special Have a Nice Death message for it; ais523 proved that this is indeed possible before you even have control of your character. He did some calculations and estimated a 1 in 3 million chance (roughly) of this occurring.
 * Psychic Radar: When blinded, telepaths can see any non-mindless monster on the current floor; extrinsic telepathy additionally lets you see the ones close to you.
 * Psycho Electric Eel: Watery areas and swamps can generate them, and they're a major hazard.
 * Public Domain Artifacts:
 * Rare Candy: Potions of gain level and wraith corpses give level-ups. Potions of gain ability (especially blessed) and the "gain ability" effect of magic fountains increase stats.
 * Reality Ensues: Since The Dev Team Thinks of Everything, a lot of interactions (and the deaths that can result from them) are surprisingly logical, often distressingly so.
 * Regenerating Health: All monsters can regenerate health gradually outside of combat, including the player; in the latter case, it's subject to how encumbered they are.
 * Required Secondary Powers: Scrolls of fire and books of fireball can't burn; wands and books of cancellation can't be cancelled; and wands, potions, and books of polymorph can't be polymorphed.
 * Receiving an artifact weapon as a sacrifice gift will unrestrict the corresponding weapon skill if it is not available, allowing you to attain at least Basic skill with that weapon. Certain artifacts also have secondary effects tied to their element (e.g. Fire Brand and Frost Brand provide fire and cold resistance).
 * Resurrective Immortality: Trolls will continually revive from their corpses unless they are killed in a way that doesn't leave a body.
 * The Wizard of Yendor will revive an endless amount of times no matter how you actually kill him, and will immediately appear in front of you to continue the fight.
 * Ret-Gone: A scroll of genocide not only kills all monsters of a given type, it removes them from the current game. If you genocide cockatrices and you were holding a cockatrice corpse in your hand and three of their eggs in your backpack, they'll all vanish. If you had a tin filled with red dragon meat and you genocide red dragons, that tin becomes empty. And you'll find yourself unable to polymorph into the genocided form now, even if you had already done so before.
 * Also, if you genocide your own race or role while polymorphed, the game will say "You feel empty inside", and you will die if you try to turn back; if you quit before dying, the death message will read "quit while already on Charon's boat."
 * Rodents of Unusual Size: Named as one of the many halluncinatory monsters. Giant rats and rabid rats are also common early-game enemies.
 * Rogue: NetHack's predecessor, which has a Shout-Out level dedicated to
 * Rule of Three: There are three alignments, with a god to each alignment, and there are three end game bosses to fight for the three items needed to obtain the Amulet of Yendor.
 * Save Game Limits: The game only allows one savefile per character in the standard mode. If you want to make backups to protect against crashes, you'll have to do that manually - any other use of backups is considered very bad form.
 * The "explore" and "wizard" modes are an exception that allow you to keep an old save file - in normal play, once a saved game is restored, the file used to hold the saved data is deleted. In explore and wizard mode, once restoration is accomplished you are asked whether to keep or delete the file, and keeping it lets you quit without saving and later restore it again (which can be used test multiple outcomes from a given scenario, for example).
 * Save Scumming: Like just about any roguelike, NetHack erases your save upon death; as explained above, it is still possible to do, but heavily discouraged unless there's an actual purpose to it.
 * Some players will do the inverse and "start scum," repeatedly starting and quitting the game until they get a favorable set of starting equipment or stats. This is usually done with wizards, due to the ridiculous (and pre-identified!) magical items a lucky wizard can start the game with. A little over 50% of all NAO games are turn-0 quits, and a good portion of those are wizards.
 * Schizophrenic Difficulty: Despite dangers like arch-liches, mindflayers, and, the game gets much, much easier after the first dozen levels or so due to the necessity of being Crazy Prepared for early monsters considered to be vastly overpowered, such as soldier ants, leocrottas, and chameleons.
 * Schmuck Bait: The community refers to tactics that are very likely to kill the player as Bad Ideas™ (Tradesnark optional). Go ahead, try that scroll labeled READ ME and see what happens.
 * Sdrawkcab Name: Yendor. The Wizard of Yendor is affectionately referred to as Rodney as a consequence, which is Yendor backwards. The origin is part-J. R. R. Tolkien inspiration, part Rogue allusion (Rodney is the default name of its player character), among a few other possible sources.
 * Sealed Room in the Middle of Nowhere: Vaults can be found on random levels and accessed by digging to them or teleporting there, which can happen by accident. A guard comes along to check it occasionally and can even help you escape if you have no other means to (though you'll have to drop your gold first). However, you can fool them through a few means
 * The Rogue quest's goal level consists of these, and unlike vaults you can't dig into them, forcing you to find another way to get at the quest nemesis.
 * Self-Imposed Challenge: Formally known as "conducts", NetHack's randomization allows for a lot of them; the distinction between an "official" and "unofficial" conduct is whether or not the game actively keeps track of how much you adhered to it. The game also has options that can alter the starting character to fit the desired conduct.
 * Blind Weaponmaster: The "zen" conduct - beat the game while permanently blind.
 * Dungeon Bypass: The main idea of "digging for victory", and often invoked by speedrunners - dig down to reach the Castle as fast as possible, snag the wand and wish up a kit, and then win the game from there.
 * Flat Earth Atheist: The "atheist" conduct involves not using any of the religious elements of the game, satisfying the technical specs of this trope. Of course, actually playing this way pretty much requires you to either know not to do these things, or die before you get to do them.
 * Full-Frontal Assault: The "nudist" conduct - in other words, no armor whatsoever, meaning you'll have to find other ways to gain vital resistances and improve your defense.
 * Kill'Em All: The game also tracks whether or not you genocide other monsters and how many; related to this, the "extinctionist" conduct requires the player to render as many monsters in the game extinct as possible by killing enough of them.
 * Pacifist Run: It is possible for a very skilled player to win the game without personally killing anything; this often requires the use of powerful pets.
 * Shapeshifter Mode Lock: Amulets of unchanging can be worn for this effect, and rings of protection from shape changers can enforce this on other monsters, forcing them into their base form. This will also happen if you genocide your race/role while polymorphed - try to change back and you will die.
 * Shoplift and Die: Shopkeepers don't take kindly to being attacked or having their wares stolen, and will pursue you until you kill them, pay them back or otherwise pacify them.
 * Shout-Out: The game shouts out Rogue in the form of the Rogue level, includes a lot of Dungeons & Dragons and Lord of the Rings references, and many more.
 * Fighting monsters while hallucinating generates a ton of them.
 * The Tourist class is basically one big Shout-Out to Discworld. The quest leader's name is even Twoflower! In addition, when Terry Pratchett passed away from Alzheimer's in early 2015, NetHack 3.6.0 (released later that year) contained a few tributes to the author:
 * Novels named after works in the Discworld series could be found in bookstores. Reading a novel displays a quotation from Pratchett's writings, and the first novel read gives 20 experience points.
 * Breaking expensive cameras may releast an imp or a homunculus, as an homage to The Colour of Magic, where iconoscopes, the Discworld equivalent of cameras, each contain a 'picture-painting demon'.
 * Squeaky board traps squeak in a specific pitch (e.g. "You hear a distant B flat squeak"); in Discworld/The Light Fantastic, a character has floorboards tuned so he can determine not only if someone is approaching but also where that person is standing.
 * in the same manner as the recurring Discworld character.
 * Book of Amber - Grayswandir.
 * Dune - Worm tooth/crysknife.
 * The Elric Saga - Stormbringer.
 * The Hobbit - Orcrist and Sting.
 * The Mikado - Snickersnee.
 * Zork - zorkmids.
 * Sidequest: The Gnomish Mines, Fort Ludios, and Sokoban are all optional; Fort Ludios also isn't guaranteed to appear in a given game.
 * Silliness Switch: Hallucinations, caused by magic or dodgy food. Non-hallucinating silliness includes kitchen sinks, tourists, cameras, Hawaiian shirts, and even the Keystone Kops.
 * Skeleton Key: Present and able to unlock any door or chest; the NetHack 3.0 series introduced the unlocking tools, and had different kinds of keys that could only open corresponding types of locks. These were removed for the skeleton key in 3.1.0.
 * Songs in the Key of Lock: One way of getting into the Castle. A (possibly unintended) side effect allows you to easily kill off most of the monsters in the castle:
 * Sorting Algorithm of Weapon Effectiveness: Somewhat subverted, both for good and ill as far as the player is concerned.
 * Spikes of Doom: You fall into a pit! You land on a set of sharp iron spikes!
 * Stat Death: If your Intelligence drops below 3 (usually by mind flayer attack, although there are other ways to do this), you "die of brainlessness". This can also occur for strength as well.
 * Stuck Items: Cursed armour can't be removed, and cursed weapons can't be unwielded. There are several ways of dealing with these problems, though only one ("remove curse") will seem obvious.
 * Stupidity-Inducing Attack: Mind-flayers have an attack that reduces intelligence.
 * Suffer the Slings: An available weapon - although not particularly effective, at least the ammunition is easy to come by. Cavemen start the game with a sling and a set of rocks, and hobbits are often found carrying them.
 * Super Drowning Skills: You can cross water by almost every conceivable method except swimming - including, it should be noted, donning an amulet of magical breathing and walking along the bottom. Thankfully, non-aquatic monsters seem to also have Super Drowning Skills.
 * Super Not-Drowning Skills: Aquatic monsters, which include snakes and all "water" monsters, can cross water tiles easily.
 * Super-Persistent Predator: "Covetous" monsters - including quest nemeses, Vlad the Impaler and the Wizard of Yendor - can warp to your location constantly, even on no-teleport levels. Rodney himself will harass you even after you kill him - he can resurrect himself and/or teleport immediately to your location.
 * On a downplayed note, humans and various other monsters (hostile and otherwise) can follow the player to another level by being on an adjacent square to the stairway or portal.
 * Super Strength: Conferred via gauntlets of power. Nymphs also seem to have this - the better for them to pick up and steal items with.
 * Super Weapon, Average Joe: Humanoid monsters can find and use wands, which can lead to very weak monsters killing the player with ease. Fans refer to this as "gnome with a wand of death".
 * Super Weight: You start at zero or occasionally one on TV Tropes' scale. Except for the Tourist, who starts at negative one. You spend the game climbing the scale.
 * Swamps Are Evil: Rooms on later floors in the main dungeon may contain swamps full of eels and fungi.
 * Taken for Granite: Can occur with Medusa as well as cockatrices, one of the game's many Goddamned Bats.
 * Talking Is a Free Action: Varies very much with the action in question. Since this is one of the earliest roguelikes and the genre staple of "nothing moves until you move" is in effect, As for what is and isn't a free action...
 * Talking itself? Ohohoho, no it ain't. Using the extended #chat command to interact with a monster will print a response and use up a turn unless the monster in question has no response to give (as opposed to simply being unable to, e.g. due to sleep or paralysis).
 * Checking your inventory is very much a free action, and is recommended before taking action in heated situations.
 * Technical Pacifist: See Pacifist Run above, and note that the requirement is that you don't personally kill anything. Leading an army of high-level pets through the dungeon and letting them slaughter everything you meet is just fine.
 * Technicolor People: Implied with the Wizard quest leader's encyclopedia entry.
 * Tech Points: You need both "skill slots" (gained through Experience Points) and a certain number of successful uses of the item/spell in question to advance a skill.
 * Teleporters and Transporters: Teleport and level teleport traps randomly send you to another tile or level. Vaults may have dedicated teleporters that send the user directly into them. Teleportation is also available via scroll and wand; both teleportation and teleport control also have ring and intrinsic forms, with the latter allowing you to select specifically where you end up. Certain characters can obtain teleport control via leveling up, and all playable characters can teleport at-will upon reaching XL 12 if they have teleportitis already (unless they're a wizard, who gets it at XL 8).
 * Mass Teleportation: Breaking a teleport wand with charges left over will cause the resulting magical blast to randomly teleport monsters caught inside it.
 * Random Teleportation: Intrinsic teleportation and extrinsic teleportation from a ring is known as "teleportitis", which will teleport you at random while moving. Leprechauns and nymphs teleport after successful theft attacks, and also teleport at random while moving - fittingly, their corpses are a potential course of teleportitis. Tengu also get around by teleporting, and eating their corpses can convey both teleportitis and teleport control.
 * Teleport Interdiction: A "no-teleport" condition occurs in the Sokoban branch, the home and goal levels of the quest, the Castle, the Valley of the Dead, and several other levels. Covetous monsters get to ignore this, however.
 * Teleport Spam: "Covetous" monsters such as quest nemeses and some end bosses will constantly warp around you to attack, as well as teleporting to the up stairs to heal themselves when needed.
 * Throw the Book At Them: An unusual move, but it's possible here - and if it'll save your behind, you shouldn't discount it. Spellbooks can also be wielded.
 * To Hell and Back: The bottom (second) half of the game takes place in Gehennom. Earlier NetHack versions literally had Hell instead, complete with
 * Tomato in the Mirror: "Who do you think you are, ?"
 * Too Awesome to Use: Averted with a vengeance, since you practically have to use powerful items early and often to survive at all. If you come in with the hoarding attitude, it can take a while to get used to the idea that it's OK to use two charges from your wand of fire on dungeon level three as long as you don't die.
 * One clear example is the scroll of scare monster. Compared to the more easily-engraved and reusable Elbereth, it can scare monsters that even the former wouldn't ward off and works while you're blinded. You don't even have to read it - just stand on it and it'll work its magic! The catch is that you get to drop it once or maybe twice before it crumbles to dust the next time you pick it up.
 * Touch of Death: Many high-level spell casters can do this, including one of the end bosses. Getting the proper preventative gear is a early-game priority.
 * Trademark Favorite Food: Elves get the most out of the already-filling-for-its-wight lembas wafer; orcs tend to prefer raw meat and even tripe, and despise lembas.
 * Trial and Error Gameplay: The player is supposed to make out most gameplay mechanics this way. In a game with an immense game world, permanent death, and most errors leading to said permanent death. No wonder that players doubt the possibility of ascending (winning the game) without reading spoilers. That said, the game does provide an Oracle, a special monster which gives valuable advice about the game, but she has great limitations on her consultations. There's also the in-game guides.
 * Turn Undead: Available through a spell, a wand, and a class attribute. Due to liberal application of Just for Pun, you can also use it to
 * Underground Monkey: The standard game is constructed entirely of ASCII characters, leading to a lot of creature-overlap. You definitely still don't want to confuse a dwarf king with a mind flayer (both are a purple h). Or a Mordor orc with a floating eye (one a dark blue o, one a dark blue e.) Various alternate tilesets can be used to supply more information.
 * As a more traditional example, some monsters have elemental variants that are resitant to their element's damage, and eating their corpse may confer that resistance.
 * Unicorns: One for each of the three alignments, and they're even eligible for riding as steeds. All three will try to keep a knight's move away from you, and you'll need to be pretty fast or sneaky to get next to one. Also, killing or sacrificing one of your own alignment is a really Bad Idea.
 * Unexpected Gameplay Change: The Rogue Level, which is a level that resembles Rogue. Monsters don't leave corpses upon death, and doorway cannot be entered diagonally.
 * The Sokoban branch prevents teleporting within its levels and won't let you move boulders diagonally until you complete the floor; unlike the namesake game, boulders can be created, broken or squeezed past, albeit at a Luck penalty for each offense.
 * Unusable Enemy Equipment: Averted; with the exception of most corpses, if an enemy has it, you can kill them and use it - provided it doesn't kill you first. Monsters have a starting inventory and also death drops, it can be hard to tell the difference if the monster dies without a chance to use the item. Getting particular items such as the wand of death, the potion of gain level, and off enemies is particularly frustrating.
 * "That was my prized wand of nothing, You Bastard! I was saving that!"
 * Unwinnable: If you before, you'll be unable to.
 * Unwinnable by Insanity: In fairness, both of these are things you essentially have to go out of your way to do in most scenarios.
 * Useless Useful Stealth: Averted - stealth can be a very good intrinsic to have when clearing out monster-filled zoos such as the one in Sokoban. Even in a scenario where kicking or causing something to explode wakes the entire room of monsters up, you still have plenty of other crowd control skills you can fall back on. Stealth also has multiple sources (including some elven gear), and some roles gain it through leveling up.
 * Video Game Caring Potential:
 * Helping a monster out of a trap might make it peaceful, and you also might get an alignment boost if you're Lawful.
 * Players consider it very poor form to mistreat Izchak (named for deceased DevTeam member Izchak Miller), despite shopkeepers being generally maligned by everyone; often, he is even spared by extinctionists.
 * Video Game Cruelty Potential: Have a chat with the nurses. They're not mean! They'll go right on trying to get you to take off that armor and put away that weapon. They'll heal you! And they'll keep trying to heal you even as you chop them up and tin them with your tinning kit.
 * Video Game Cruelty Punishment: Your patron god has very firm ideas on what is and is not right action. This doesn't necessarily mean you're supposed to be well-behaved - at minimum, you're not supposed to be caught.
 * Or, in some people's minds, it means surviving the very wrath of God. Which is doable. And best of all? If you do, your god says "I believe it not!"
 * Villain Teleportation: "Covetous" monsters can warp to you freely, even on no-teleport levels, and will teleport to the upstairs to heal - and, with a couple of exceptions, they are always hostile towards you.
 * Wafer-Thin Mint: If you're satiated, then eating anything - even an insubstantial wraith corpse - has a chance of causing you to choke to death... and that wraith corpse doesn't give the player a warning beforehand.
 * We Buy Anything: Subverted; most shops outside of general stores specialize and will only buy what they sell, and all shops have a limited amount of money with which to buy stuff from the PC, although shopkeepers will offer store credit instead when they can't pay you in cash anymore. Played straight in that any shop will sell the player anything that comes into the shopkeeper's possession (including the items of monsters killed in the store). This can be useful for price identification.
 * Weak but Skilled: Several classes, such as the Caveman and Tourist. Also a good mindset for the player themselves, especially in the early game.
 * Weaksauce Weakness: Several late-game monsters have surprising weaknesses.
 * Weapon of X-Slaying: Commonly referred to as the "Banes" - Orcrist and Sting (orcs); Ogresmasher, Giantslayer, Werebane, Demonbane, Dragonbane, and Trollsbane (Exactly What It Says on the Tin); Scepter of Might (non-coaligned monsters); and Sunsword (undead).
 * Parodied by Vladsbane, a reference to how Vlad the Impaler was so easily defeated that players made it a point to use the most impractical weapons possible for some semblance of a challenge.
 * A Winner Is You: If you fight, sneak, and fast-talk your way through 45 to 53 levels of Everything Trying to Kill You, both ways, plus 5 bonus endgame levels, over what can be weeks of playtime and hundreds of thousands of moves, you get this:
 * What Measure Is a Humanoid?/What Measure Is a Non-Human?:
 * For non-chaotics, murder penalties only apply if you kill "always peaceful" humans (e.g. watchmen, shopkeepers, etc.); many other peaceful non-human monsters incur a minor alignment penalty in comparison unless they were coaligned or you killed them without angering them.
 * On that note, player characters are generally forbidden from sacrificing members of their own race (unless Chaotic) or eating corpses of the same race (unless the player is an orc or Caveman). Every other being they come across - including many sentient and even sapient monsters? Fair game!
 * With This Herring: The Tourist class is the most obvious example, but several other classes qualify.
 * Wizard Needs Food Badly: In an exception to Bottomless Bladder, the PC needs to eat, and will begin fainting if they get hungry enough, eventually dying of starvation. If your character class is a Wizard or Valkyrie, or your character race is elf, the game will actually use this phrase, in one of the game's many Shout-Outs.
 * A Worldwide Punomenon: Levitating characters will sink if they float over a sink. Drinking a cursed potion of gain level causes a character to move up a dungeon level. Scrolls of mail, on UNIX systems, are delivered by a mail daemon. If you try to identify a wand of striking by engraving something on the floor, you'll receive a message that it "unsuccessfully fights your attempt to write". And that's just for starters! Boy howdy, The Dev Team Thinks of Everything.
 * You Will Not Evade Me: Once you've found him and woken him up, The Wizard of Yendor will reappear periodically wherever you are, and taunt you for thinking you could elude him (if he was alive and on a different dungeon level). A slightly different taunt appears if he was killed instead.
 * Several high-level covetous monsters, including the Wizard, will also teleport to your location constantly as long as you are on the same level. All of them combine this with Get Back Here Boss as mentioned above for maximum annoyance.
 * Several high-level covetous monsters, including the Wizard, will also teleport to your location constantly as long as you are on the same level. All of them combine this with Get Back Here Boss as mentioned above for maximum annoyance.