History DemonicSpiders / EtrianOdyssey

* Enemies with PowerfulButInaccurate attacks should never be underestimated. They will often have a way to reduce or disable your evasion so that those attacks will hit and likely get multiple party members killed.

* Forest Shrimp, found in the Waterfall Woods behind the Star and Moon Doors. They have a special attack that hits the entire party and has a high chance of causing paralysis. They're also tough as nails, being highly resistant to both physical damage and Ice damage (which is a problem, since the Golden Idols that infest this area are ''only'' weak to Ice damage). Even more irritatingly, they tend to show up with Demon Octopodes, which have an attack that binds your entire party's legs, making it that much harder to escape them.

* If an enemy is weak to all elements, all physical attack types, or both, ''[[SchmuckBait watch out]]''. They will often have a skill that is designed to punish those who try to capitalize on those weaknesses, such as a way to inflict the Curse element or a LastDitchMove that inflicts debilitating debuffs.

* Hexgourds, the FOE of the Illusory Woods, are not just aggressive [=FOEs=], but are also capable of ''following you through walls''. The moment you've earned its attention, there is no escape except by returning to town. If you do try to engage in battle, you quickly realize that ''all'' your attacks do ScratchDamage to it, making battle a rather futile endeavor. There's a reason the game warns you to keep an Ariadne Thread on hand.

* Iron Crabs are found on the final floor of the bonus stratum in ''The Millennium Girl''. They are docile, resistant to most forms of attack, but if you kill any of its allies it will [[BerserkButton turn aggressive]] and spam Scissor Wrath which can destroy even the strongest of parties. The game loves to pair them up with other deadly encounters like Red Corpuscles that with an [[OneHitKill instant death attack]], but worst of all is when it gets paired with Evilroots which take the time to charge a [[TotalPartyKill very accurate party-wide instant death attack]]. [[MortonsFork You either kill the Evilroots and die to Scissor Wrath, or you kill the Iron Crabs (or fail to run away) and die to Last Cry...]] [[note]]Or die to the Depth Dancers that are swooping in on your position.[[/note]]

* Anomalocaris in the DLC 31st floor of ''The Fafnir Knight''. The floor consists of large rooms devoid of random encounters... because of these guys. Not only do these [=FOEs=] have an astounding sight range of '''5''', they also move randomly, making it nigh-impossible to traverse the floor without engaging one in combat. It only has two attacks: one that drains TP and can completely bind its target, and another that does splash damage with a chance of instantly killing anyone hit. Between these attacks and a high HP count, it's difficult to defeat a single one of them without experiencing significant loss of TP. On top of that, if you leave the floor, '''all of them respawn''' -- you have to beat most of the floor in one sitting since you cannot kill the Anomalocaris to grant safe passage on return trips. Mercifully, a shortcut exists connecting the entrance to the boss so that you can challenge it with a fresh party, but it's a long trip through the floor to reach it, and the last room with these critters contains '''five of them'''.

* Several monsters can perform {{Combination Attack}}s, with one or more monsters "standing ready" and another monster performing the attack itself with the aid of its partners. If at least one of the participiant monsters isn't killed before the attack takes place, or if you at least don't render the main user unable to use the skill (binds, Panic, etc.), expect to see at least two or three dead bodies in your party, or even a GameOver.

* Archpixies in the Illusory Woods have two skills: One instantly kills a party member, the other can cause triple-bind on a row. They're also immune to all ailments barring instant death, and take only ScratchDamage from pure elemental attacks. If a group of ''four'' show up, it's best you run immediately. Your one hope is a head bind, but good luck if your binder gets killed or bound.

* Across various games, there are also monsters that are weak on their own, but if you don't kill them fast enough, they will summon or transform to F.O.E.-type monsters. A really nasty surprise if you don't expect it.

* Moth-type enemies have a nasty habit of spreading ''confusion'' to your party, rendering them uncontrollable and unable to dodge the Moth's other attacks. God help you if your healer's hit.

* Cocky Capacitors are found in the Buried Castle. On their own, they're pathetic, incapable of any form of offense and actually opting to run away from the party. When two meet, though, they fuse and become a lot more powerful and aggressive, moving fast enough to chase down the party. Not helping matters is the cramped environment making escape difficult. Defeating it is not easy either -- when it falls to low health, it [[AsteroidsMonster splits into four small Capacitors]], and if they are not killed quickly they fuse into a large Capacitor at full health, starting the fight over with your resources depleted.

* Archpixies in the Illusory Woods have two skills: One instantly kills a party member, the other can cause triple-bind on a row. They're also immune to all ailments barring instant death, and if a group of ''four'' show up, it's best you run immediately. Your one hope is a head bind, but good luck if your binder gets killed or bound.

* Muskoids return in the final dungeon, and this time they can petrify the entire party without having taken any damage! Although the game no longer gives you an instant game-over if the whole party is petrified, on top of the ailment wearing off mid-battle, a petrified party is still ripe pickings for the Muskoids' companions which shower you in elemental attacks.

* Asura Cicadas spread a severe defense debuff on your party, leaving them more vulnerable to other more deadly enemies. When they die, however, they unleash a party-wide ice attack which is likely to cause a TotalPartyKill if the defense debuff is active.

* Any enemy who has Instant Death abilities, especially ones that hit multiple characters, *especially the ones who come in packs*. While some are balanced out by requiring a turn to use to give time to bind or use a sonic bomb to stop it, it's still easy to ether mess up or have them paired with disabling enemies and quickly end a game.

* The third floor of Ginnungagap in ''The Fafnir Knight'', also ThatOneLevel, is crawling with Death Walls. These disguise themselves almost perfectly as walls, and don't react until the player stops facing the party directly at them. They also don't show up on the map until they start moving, and they can quickly close the gap between them and the party. Get caught in a battle with one, and the Death Wall also prevents you from fleeing the battle (except on certain turns), forcing you to expend a Return Flute. The later rooms of the floor also involve you navigating around 2 to 3 of them at the same time.
* Anomalocaris in the DLC 31st floor of ''The Fafnir Knight''. The floor consists of large rooms devoid of random encounters... because of these guys. Not only do these [=FOEs=] have an astounding sight range of '''5''', they also move randomly, making it nigh-impossible to traverse the floor without engaging one in combat. It only has two attacks: one that drains TP and can completely bind its target, and another that does splash damage with a chance of instantly killing anyone hit. On top of that, if you leave the floor, '''all of them respawn''' -- you have to beat most of the floor in one sitting. Mercifully, a shortcut exists connecting the entrance to the boss so that you don't need to fight through them again after unlocking it, but it's a long trip through the floor to reach it, and the last room with these critters contains '''five of them'''.

* Dreamrays in the BonusDungeon love to spam a party-wide ice attack that has a good chance of putting them to sleep. They are also immune to the bind which would otherwise shut down this attack, and are resilient to most ailments, making them difficult to shut down before they act.

* Petaloids their variants in ''Etrian Odyssey'' loved nothing more than to chain-sleep your entire party, thus allowing the other enemies to unleash a world of hurt on you. They appear in ''Legends of the Titan'' as well, although thankfully they'll only target one party member... [[OhCrap unless you damage them]].

* Fire Squirrels, found in secret areas of the Jagged Reach, serve as a very nasty CallBack to a series of SchmuckBait events in ''Heroes of Lagaard'' and its remake. Not only does it hit fairly hard, if it's the last one standing (and it almost always will be, since it's grouped with much weaker enemies) it uses Burning Thread, which '''destroys an Ariadne Thread'''. Floor Jump does not exist in this game, so they can easily strand you if you don't kill them first.

* Another star in the ending of the second Stratum of ''Heroes of Lagaard'' is the Poseidon. A huge grass brachiosaur with about double the HP of almost everything else in the floor, which doesn't hit for all that much less than the areas F.O.E.s, and which has a move named Scurry that hits your whole party - yes, including the SquishyWizards in your back row - for huge damage. Additionally, it seems fond of blindsiding you (which poses the question of how in blazes you get blindsided by a goddamned Brachiosaurus), which means he gets a free turn to maul you into paste. And he almost never appears alone, to add insult to injury. Good luck avoiding them, since all resource-gathering points have a random chance of giving you a battle instead of an item, and Poseidons are a common opponent in these events.

* The Muckdile or Dinogator in both ''Heroes of Lagaard'' and ''The Fafnir Knight'' return on the 30th floor as one of the toughest random encounters in the game, with [[BossInMookClothing 5-digit HP and devastating attacks]]. And you need to hunt one for one of the lategame quests.
** The Muckdile is one of the only enemies immune to Stun, where anything else in ''Heroes of Lagaard'' had some vulnerability. Its Bite attack does quite a number to the party, but if it were fully bound, it instead starts using Frolic which fully binds the party. Clearly it was meant to be a counter to Force skills...
** The Dinogator in ''The Fafnir Knight'' trades Stun immunity for an even deadlier attack - Pout hits the party randomly 10 times, and is used at low HP, which can spell an untimely end to a long and grueling battle. Frolic also no longer triggers on it being fully bound -- and it's now used in response to the Dinogator being affected by any one bind!

* Colossal Ropers in ''Beyond the Myth'' don't seem all that bad when they're first encountered on 3F, but come 5F and they often come into battle with Rabid Acorns as reinforcements. It will then throw those Acorns at you for massive damage to the whole party, quite possibly a TotalPartyKill, if you don't either bind the Roper's arms or kill at least one Acorn first.

* Fire Squirrels, found in secret areas of the Jagged Reach, serve as a very nasty CallBack to a series of SchmuckBait events in ''Heroes of Lagaard'' and its remake. Not only does it hit fairly hard, if it's the last one standing (and it almost always will be, since it's grouped with much weaker enemies) it has an attack that '''destroys an Ariadne Thread'''. Floor Jump does not exist in this game, so they can easily strand you if you don't kill them first.