History VideoGame / EyeOfTheBeholder

** The ''flesh to stone'' spell can turn monsters into statues, that can then be broken with just one hit. The visual effect for such isn't very polished, though, the affected monsters just becoming grey silhouettes with no details.

* BigCreepyCrawlies: Giant spiders in ''[=EotB1=]''; more spiders, mantis people and giant wasps in ''The Legend of Darkmoon''.

* ControlRoomPuzzle: Subverted in ''[=EotB1=]'': in one of the later floors, there is a room labeled "Combination Lock -- Be Quick" with 5 switches and a group of items on the other side of a pit (by this point, the game has already established that pits can be moved or gotten rid of entirely). Each time a switch is hit, the party must move quickly to dodge a fireball that gets launched from the other end of the room. The player obviously thinks that they need to find the right combination to get rid of the pits; the catch, though, is that it's actually impossible to remove the pits, the switches do nothing, and it's just an excuse to frustrate the player.
* CopyProtection: ''[=EotB1=]'' requires entering a word from the manual.

** Between the first two games, beholders. Xanathar is the FinalBoss of ''[=EotB1=]'' and the only one seen in this game; in ''The Legend of Darkmoon'' there's a dungeon level full of them. Your party should be high level enough to handle them at the time, but they're still to be fought with caution, especially when confronted by a pair.

* FoodAsBribe: The consumable Kenku eggs found on level 7 of ''[=EotB1=]'' can be used to bribe the Drow guards, making them abstain from attacking you.

* TheGoomba: The kobolds in ''[=EotB1=]''.

** ''[=EotB1=]'':

** ''[=EotB1=]'': Explosives Runes blast in your face when read (but only in the remakes).

** The rust monsters in ''[=EotB1=]'' will eat any metal item.

* MrExposition: In ''[=EotB1=]'', you meet a robed mage around the sixth level. Before attacking you, he explains about Xanathar's plot, the dwarves, the drow and his own plan to eventually strike Xanathar after the beholder's conquest of Waterdeep.

** The complete disappearance of the ''stoneskin'' spell in ''The Legend of Darkmoon'', even with an imported party from ''[=EotB1=]'', for whom it vanishes from spellbooks (and a ''stoneskin'' scroll can't be saved either). The spell is a big [[GameBreaker/RolePlaying Game Breaker]], because it negates damage from physical attacks, for a number of attacks and no finite duration, allowing the player to recast the spells with the ability to rest without limit.
** The TurnUndead power also got modified between the two games. In ''[=EotB1=]'' it is an automatic function, as long as the character is holding a holy symbol. Starting with ''The Legend of Darkmoon'', it becomes an action like any spell-casting, though not limited in use.
* NonCombatEXP: ''[=EotB1=]'', the first level has various XP reward for getting through the dungeon, examining walls, etc.
* NormallyIWouldBeDeadNow: In ''[=EotB1=]'', Xanathar's DisintegratorRay, by ''AD&D'' rules, should kill instantly, but instead inflicts exactly 100 HP of damage. NoOneShouldSurviveThat, right? Well, except if you have a high-level dwarf fighter with 19 in Constitution and the maximum possible on each roll (thanks to SaveScumming and LevelGrinding)... that character can perfectly have more than 100 HP by the end.

* PoisonMushroom: In ''[=EotB1=]'', some apparently useful potion flasks contain poison. And in this game, it's not easy to identify them early on (although SaveScumming helps).

* RemixedLevel: ''[=EotB1=]'''s first sewer level may be different on the playthrough, the decision point is made at the first junction.

* TurnUndead: A power for the cleric or the paladin, along with the ''D&D'' rules. In ''[=EotB1=]'' it is an automatic function, as long as the character is holding a holy symbol. Starting with ''The Legend of Darkmoon'', it becomes an action like any spell-casting, though not limited in use.

** At one point, you have the option to help out a beholder stuck inside a circular hole on the ceiling. If you choose so, it thanks you... and then immediately attacks the party because it's hungry.

* WakeUpCallBoss: The giant spiders and the whole fourth level of the first game can be considered this. The layout of the level can get confusing, the spiders can poison you and you probably only have limited means of curing the poison status at this stage.
* WarpWhistle: The games feature magic portals that are activated by special "stone" items, and transport you elsewhere in the dungeon. Each portal has carvings of seven items along its frame, with the eighth empty spot indicating which item should be used. They are usually two-way, however ''[=EotB1=]'' has one portal where the destination spot and the return spot are split and in separate places. This can become a trap since it sends you to a deeper level that you may not be ready to explore yet. ''The Legend of Darkmoon'' streamlined the portals to where a portal can connect to any other portal, and there is no missing spot. Instead which stone item you use on a portal determines your destination. This means it can end up being a one-way trip if you have not discovered the local stone item yet.
* WarpZone: ''[=EotB1=]'' has a room sporting five of the aforementioned magic portals in the same place.

* BigCreepyCrawlies: Giant spiders in ''[=EotB1=]''; more spiders, mantis people and giant wasps in ''[=EotB2=]''.

* BraggingRightsReward: In ''[=EotB3=]'', an optional dungeon called The Mausoleum near the start of the game gives you a "Rod of Restoration" as a reward... guess where the only enemies that use what it cures are.
* ClingyMacGuffin: There's a few undroppable cursed items in ''[=EotB2=]'' that will weld themselves to your hand. However, getting rid of them just require one ''remove curse'' spell, which is accessible to both mages and clerics. So it's only a problem if your characters are too low level to cast it (or can't rest and regain spells, but then you have a much bigger problem on your hands).

** ''[=EotB2=]'' has two No Exit examples. To make it all the more frustrating, both of them also give you very good magical equipment, which easily leads the player to think there must be ''some'' way to get out and keep the stuff.

** ''[=EotB3=]'' has a down staircase, which leads to an infinite dead-end room if you go through without completing some action first.

** Between the first two games, beholders. Xanathar is the FinalBoss of ''[=EotB1=]'' and the only one seen in this game; in ''[=EotB2=]'' there's a dungeon level full of them. Your party should be high level enough to handle them at the time, but they're still to be fought with caution, especially when confronted by a pair.
** The first guardian daemon you encounter in ''[=EotB2=]'' is a MacGuffinGuardian, and a dangerous fight since you confront it at the end of a section where you can't use magic or healing. (Plus, it's a lengthy corridor where you have nowhere to hide from its {{fireballs}}.) Later in the game, though, guardian daemons are the standard monsters of a level.

* GiantMook: ''[=EotB2=]'' places frost giants within one of the dungeon levels. They are crawling within the 10' cube, and are able to hit three characters in a single punch.

* HelpImStuck: In ''[=EotB2=]'', there is a round hole in the ceiling allowing to rise up to the next floor thanks to a "whirlwind" button. When found, a beholder happens to be stuck inside, with just its mouth, central eye and a few eyestalks peeking through. It asks the adventurers for their help to be unstuck -- one of the rare times a beholder deign speaking to the party rather than attacking on sight.

** In ''[=EotB2=]'', there is a puzzle for which the clue is given of "faith is the key." In the puzzle, a sequence of four doors in a corridor must be opened by pulling four levers such that each lever opens a pit in front of the previous one, meaning that the fourth door-opener lever is inaccessible across a pit (albeit not a [[BottomlessPit bottomless one]], since the game doesn't have those). The trick, in this case, is to open the first three doors, walk down the partially opened corridor, and push a [[PixelHunt misaligned brick]] on the wall, at which point it becomes possible for the player to walk on top of the pit in order to pull the fourth lever and open the last door.

** ''[=EotB2=]'':

* MacGuffinDeliveryService: ''[=EotB3=]''. A mysterious figure sends you off to kill a lich. Once you finally manage, it turns out [[spoiler:[[OurLichesAreDifferent to have been a good lich]] (despite the fact that he, you know, tried to kill you) and the mysterious figure teleports in, gets an unnamed MacGuffin, reveals himself to be the evil dark god, and flees. The rest of the game is spent chasing him]].

** ''[=EotB2=]'': Gas spores explode like a fireball if they take even a mere scratch.

** The gelatinous cubes in ''[=EotB2=]'' can also destroy items on a hit.
** The black puddings in ''[=EotB3=]'' will eat your weapons if you attack them in melee.

** The complete disappearance of the ''stoneskin'' spell in ''[=EotB2=]'', even with an imported party from ''[=EotB1=]'', for whom it vanishes from spellbooks (and a ''stoneskin'' scroll can't be saved either). The spell is a big [[GameBreaker/RolePlaying Game Breaker]], because it negates damage from physical attacks, for a number of attacks and no finite duration, allowing the player to recast the spells with the ability to rest without limit.
** The TurnUndead power also got modified between the two games. In ''[=EotB1=]'' it is an automatic function, as long as the character is holding a holy symbol. Starting with ''[=EotB2=]'', it becomes an action like any spell-casting, though not limited in use.

* ScrewTheMoneyIHaveRules: In ''[=EotB3=]'', if you have a paladin in your party, you won't be able to dig up graves for valuables.

* SoLongAndThanksForAllTheGear: Played completely straight with one character in ''[=EotB2=]'' . A {{halfling}} you meet early in the game is locked up, and you have the option to free him. However, the first time you camp with him in the party, he runs off and takes, not the equipment he's carrying specifically, but ''some of the gear of the sleeping party members''. Well, you should have expected it; he's a Thief (the CharacterClass). He even leaves a note basically invoking this trope by name.

* StockFemurBone: Most of the bones found in ''[=EotB2=]''. They can be used as clubs.

* TurnUndead: A power for the cleric or the paladin, along with the ''D&D'' rules. In ''[=EotB1=]'' it is an automatic function, as long as the character is holding a holy symbol. Starting with ''[=EotB2=]'', it becomes an action like any spell-casting, though not limited in use.

* UngratefulBastard: In ''[=EotB2=]''...

* UnintentionallyUnwinnable: From ''[=EotB2=]'', in the level with flying cobras and gas spores, you can encounter a priest of Darkmoon lost in the maze and standing on a pressure plate. If you kill him, [[DeadEndRoom the door to the room closes with no way to open it]], forcing you to reload the last saved game. There is a way to keep the door open, however (to get the treasures next to the priest), by luring beforehand a monster into the frame and paralyzing it or turning it to stone; the door then can't close even if the pressure plate is released. This clearly wasn't anticipated by the makers, though, since the whole level gets wonky afterward. Notably, the monsters now all look like priests (but still makes flying cobras sound and can poison you). Not quite a GameBreakingBug as you can still continue playing, but if you've done so before solving the riddle for exiting this level -- which is done by feeding various items to a series of magic mouths in the walls -- then you are stuck because the magic mouths are no longer there.

* UnnaturallyLoopingLocation: ''[=EotB2=]'' features a seemingly endless corridor in an already frustrating level, thanks to one of the "sneaky teleporters" of the game, who sends the party back a few squares with no visual clue. Leaving an item on the floor allow one to realize what's going on. There's no way to ever reach the other end of the corridor.

* WarpWhistle: The games feature magic portals that are activated by special "stone" items, and transport you elsewhere in the dungeon. Each portal has carvings of seven items along its frame, with the eighth empty spot indicating which item should be used. They are usually two-way, however ''[=EotB1=]'' has one portal where the destination spot and the return spot are split and in separate places. This can become a trap since it sends you to a deeper level that you may not be ready to explore yet. ''[=EotB2=]'' streamlined the portals to where a portal can connect to any other portal, and there is no missing spot. Instead which stone item you use on a portal determines your destination. This means it can end up being a one-way trip if you have not discovered the local stone item yet.