Demonic Spiders: Massively Multiplayer Online Games
Demonic Spiders are right up there with loot ninjas and random disconnections in the ranks of "Most annoying things you'll find in an MMO."
In Phantasy Star Universe, there are numerous enemies that fit this trope. The following are most of the most menacing enemies.. but this is a game where any enemy can have very powerful Status Buffs, including halving all damage they take and doubling all damage they deal.
Darbelans are giant evil SEED forms that have a spinning attack of doom and a short-range power spell (Damdiga). Fortunately, they are rare enemies.
Gaozorans are Black Mage type enemies with *RIDICULOUSLY* overpowered spells. Also, they Teleport Spam around the room and have a fair amount of hit points. Resistant to magic.
Komazli are much like Gaozorans, but with Grants and the ability to heal themselves.
Dilnazen are giant sword-armed enemies that jump at you from half a screen and launch knockback inducing purple energy bolts. Oh...and they're practically immune to ranged attacks.
Phantasy Star Online has plenty of them too, with the worst of them all being the Delbiter. This is an enemy that will charge at you as it spawns, then charge at you again if it hasn't closed the distance, will shoot a fast-moving laser at you almost instantaneously, has an almost unavoidable close-range attack, will counter-attack with a battle aura that will either confuse, stun, or outright kill you, and will completely stop flinching from your attacks after losing a certain amount of HP. God help you if you ever end up in a room with more than one of these bastards at one time.
In City of Heroes, the Malta Group's Sappers, whose signature ability can completely drain your endurance unless you have some protection against it (none of which is quite 100% as it is). And the Sappers are just minion-ranked enemies.
The Malta group in general is extremely aggravating to fight. Whether it be their 30 second stuns (no... seriously), their auto-turrets flying gun drones, their Gunslingers, and their Zeus Class Titans that can decimate you if you're at juuuuust the right distance. And let's not forget their sister organization, Knives of Artemis. They are an utter nightmare to fight in large groups. They all use caltrops, they all have long-duration tranquilizer darts which stack and put you to sleep for a second (detoggling everything), and they all use the same sort of stun grenades as Malta. In a large group, you're basically fixed in your location, stunned (even if you have a resistance ability, it will get taken off by tranquilizer dart stacking), and just waiting for the psycho bitches to slaughter you. They are the ultimate demonic spiders.
Electric Armor Brutes are nigh-immune to endurance drain by the level Malta appear at and laugh at Sappers. None of the stun grenades or tranquilizer darts are unresistable, but they have such a long duration that you can easily run to the next group and get detoggled because their darts/grenades stacked with the effect that was still on you from the previous group.
Malta lieutenant and boss level stun grenades last forty-five seconds against Heroes or Villains of the same level. These enemies can kill a player character in less than ten.
Stone Armor is basically immune to stun/sleep and resistant to endurance drain, thanks to Rooted. Unfortunately, you're also ground-bound and slow as molasses, which is a problem once the sappers start to teleport and fly.
The Tsoo are hardly slouches, either. You encounter them at relatively low levels, and they're presented as being little different from the fire- and darkness-themed beginning gangs, or the elemental- and superstrength-themed gangs of the next tier—threats, to be sure, but nothing special. Then you actually meet them. Their basic minions will attack in swarms, throw Caltrops (slowing you dramatically and placing a DoT on you for as long as you are standing on them... also, AI-controlled pets will go berserk trying to escape them), put you to sleep, lock you down completely, stun you (and doing obscene amounts of damage), lower your defense, siphon off your attack power so that your damage output is crippled and their own is sent through the roof, and siphon off your speed so that you're reduced to a desperate crawl while their buddies pound you to mush and THEY'RE zooming around the level at seventy miles an hour screaming "Yipa, yipa, andale, andale!" All this while their Lieutenants are teleporting in and out, healing their compatriots, blowing you halfway across the map with their hula-hoop tornado, reducing your accuracy to the point that you couldn't hit the broadside of a barn from the INSIDE, and occasionally punching you in the face. Oh... and their massive quantity of boss-types (third-tier enemies) have most of the abilities of their minions, as well as being able to do fun things like fly, turn invisible, knock you around like a ragdoll in a number of entertaining fashions, poison you, immobilize you, hurl random chunks of the landscape at you, set you on fire, freeze you solid... it makes doing Tsoo missions interesting, believe me. Thankfully, they're mostly confined to a very narrow level range.
The Tsoo are not nearly as annoying if the character possesses status protection and does not try to engage too many of them at once. A Controller or Dominator can easily shut down the Sorcerers before they can cause a problem.
The Carnival of Shadows illusionists, with their ability to phase, becoming untouchable, even when they're not supposed to be able to do anything, are merely annoying. Master illusionists, on the other hand, can do the phasing thing, and if you don't keep them shut down, will summon in short order about five pets (some of which summon additional pets), drastically altering the odds against you. The Ring Mistresses, with their ability to completely shut down your endurance recovery, are decidedly nasty, too.
Night Widows. Are highly resistant to holds and other basic forms of control, which sucks when your only defense is holds. And throw a smoke grenade so you can't see anyone else, which means you can't hold anyone else, which sucks when your only defense is holds. Fortunately you can just pop an Insight (like an accuracy potion) to see again, but when you don't have an Insight...
Some powersets have perception bonus powers which essentially nullifies the smoke grenades effect. There is also an invention enhancement that any character can obtain that has the same effect, as well as a power from the Pools (Tactics—admittedly requiring the commitment of a power pool selection and two power choices, which is non-trivial) that also grants Perception.
Rularuu are an entire faction of Demonic Spiders, intentionally made as such. Floating eyeballs that hit hard and are nearly impossible to dodge and summon more eyeballs, little imps that spam holds and fuse together into bigger imps with full health when damaged, big brutes that boost every bad guy's damage and health while draining your resistance and endurance, and spindly gold humanoids that spam more holds and buff defense and send psychic damage everywhere. For over a year after their release into the game, one of their archvillain-level bosses could kill tanks in a single shot. They all have boatloads of Status Effects to pass out. Oh, and they're in the most irritating zones to travel through, and the longest group missions in the game. Thankfully, most players have little reason to go there.
Ballistae used to detoggle and knock back with a single, ranged, spammable attack. While that's nothing too dangerous for archetypes that never had mez protection in the first place, people used to shrugging off mezzes and knockback were in a world of hurt as most of their defenses would no longer work at all. They also hit ridiculously hard. This got so bad that the detoggle effect eventually had to be removed.
To a fairly weak Scrapper with super reflexes who depends on his toggle powers to not be hit the Freakshow with their stun attacks and large smashing damage are Demonic Spiders, things are going fine until wait I'm stunned, wait I'm down to 5% hit points. Combine with the fact that not only do they self heal but they can self resurrect...
Thankfully, every single one of those listed Demonic Spiders has a very effective counter. A Scrapper supported by a Kinetic Defender will scythe through Knives of Artemis. Controllers and Dominators can lock down the most annoying mobs like Sappers or Sorcerers. A Ballista is helpless if you reduce its accuracy. And so on, and so on. The problem is pulling out said counters before the Demonic Spiders overwhelm you.
World of Warcraft has Monstrous Kaliri in Skettis. They're fast patrolling aerial monsters that, once locked onto your ass will chase you down, slow you down, and eventually knock you off your flying mount unless you have immunity from daze, and only tank specced characters with sufficient defense will have this blessing. If you can't escape them, then your only hope is to land somewhere safely so you can kill them at your leisure, and 'safe' landing points are rare enough as it is in Skettis. Blizzard even upgraded their AI, changing your chances to escape from "low" to "extremely slim".
Also the trolls of Zul'Mashar. One type will immediately run for help, making it pretty much impossible to fight one at a time. Even the murlocs have the decency to wait until they've been damaged. The other turns you into a frog, and uses a Life Drain on you as you helplessly hop around on the floor. If you're playing the wrong class the only way to kill them is to wait until they run out of mana.
Similarly, Kurzen Medicine Men in Stranglethorn Vale. If you had no way of stopping a heal spell from going off or couldn't do a lot of damage quickly you pretty much had to wait for them to bleed their mana dry, as they could heal to practically full health with each heal.
Let's not forget those basilisks in Zul'Farrak that like to stun you in the middle of fights. Or all of those hostile elite mobs that are overpowered for their zones and like to come out of nowhere and attack. You know... the Sons of Arugal in Silverpine, the devilsaurs in Un'goro Crater, the fel reavers in Hellfire Peninsula, et cetera?
In Un'goro crater, those Pterrordaxes too. One variant will randomly cast fear on you once in a few seconds which makes you run around like an idiot and there is a good chance that you will aggro more monsters.
Alliance players will remember their own version of the Sons of Arugal, Mor'ladim in Duskwood falls under this category. He may have been nerfed, but players who have been playing for long enough will remember him. Looks like many of the other skeletons in the area, moves incredibly quickly, and will kill you in two hits if he gets close enough. Many a high level player would come back to this area when they could kill him and murder him over and over again. Another honorable mention from Duskwood is Stitches, mighty quest-summoned abomination. Nerfed into oblivion as of now, but he used to be so strong he devastated Darkshire on his own.
The assorted Defias thugs near the Human starting area. They aren't, but unlike every other starting zone enemy, they are hostile, and will swarm you to death unless you very carefully pick their groups apart. Oh, and they run and call for help. They have, however, been made nonaggressive in a pre-Cataclysm patch, so this no longer applies.
Defias Pillagers, level 14ish spellcasters that were located in Westfall and in large numbers in the town which contained the first dungeon most Alliance players would go through. Prior to the 2.3 patch, these guys would cast Fireballs that hit immensely hard for there level, so much so that they frequently were on the list for the top 10 most dangerous mobs (Mobs that kill the most players). They only nerfed them by just a tiny bit, though, as they still hurt like hell for appropriate player level.
How the heck has Void Reaver trash not been mentioned? All it takes is for one of your locks to miss a banish for a couple of seconds and the next thing you know, half the raid is face down on the floor from that damned sawblade spam.
Mobs with elemental immunity probably apply for most caster classes, since nearly all casters will be focusing on spells of one element. Run into an enemy (or three) that's immune to that element, and you're stuck with the spells you've been neglecting and may not even keep on your action bar. And if you rely too much on "crowd control" (read: if you're a mage) there are mobs that are immune to that, too.
Note that most of the above examples have been nerfed into oblivion with the Cataclysm expansion, which overhauled a majority of the old content and gave considerable power boosts to most classes in the early levels. Most modern instances of this trope turn up in the level 80+ zones, generally due to wonky respawning issues and mob density. The cultists in the "gauntlet" section of Twilight Highlands leading up to the entrance of Grim Batol deserve special mention. The packs are huge, the melee'ers hit like trucks, and the casters love to snare you with frost spells.
Stonecore Earthshapers in the Stonecore. If the player doesn't interrupt a certain spell, they transform into a Force of Earth, and start using AOE attacks that devastate the party.
The Firelands has quite a few, from groups of five or more Flamewalkers immune to Crowd Control, to scorpions that explode when killed, to turtles that are so strong and difficult to tank that not even trash raids that form for reputation and chances at sellable epic items will kill them.
The trash in the Lost City of the Tol'vir pitches in on this as well. Oathsworn Skinners have a very unpleasant Fan of Knives that they will keep throwing out just as often as they see fit. The Neferset Plaguebringers and Torturers can also be rather unpleasant. The first does decent damage and, much more worryingly, likes throwing out rather lengthy fears VERY liberally. The same applies to the Torturers, except theirs is a silence and will almost invariably be thrown on the healer.
Murlocs are a borderline case. Wherever they appear, you can bet there will be at least twenty of them. The Demonic Spiders part of it is that murlocs tend to run when their health gets low. Unless you kill the little bastard quickly, that one murloc you were fighting can turn into three or four.
The Mists of Pandaria version is the Virmen, literally rabbit-men where murlocs were fish-men. Come in groups, have several different versions (three small weak ones that leap at you, medium sized ones that stun from a distance, large ones that burrow/teleport and stun you, and which run off at about 1/3rd health to aggro more) and are nearly impossible to pull one at a time. Every one on one fight turns into a family reunion mosh pit. Hozen are almost as bad, in many of the places they appear.
Special mention goes to the Springtail Virmen in Valley of the Four Winds. Attacks in packs? check. Has a bleed that deals approximately 17,000 damage a tick at maximum stacks? Check. Are they everywhere in the cave you're supposed to save a quest target? Check. These guys pose a threat even to a Level 90 player.
In the Timeless Isle, the Molten Guardians, as well as the King Mook, Cinderfall, count. They often use a frontal cone attack that can be dodged, but will sometimes spew fire all around them, which is almost impossible to avoid for melee classes and can be dangerous if you're just passing through. To make matters worse, griefers like to pull them to where the rival faction is fighting Ordos.
Siege of Orgrimmar has a few. There are the Lingering Corruption adds before the fourth boss, which apply a debuff on a random player when they die that damages them and everyone close to them after a few seconds or when it's dispelled; too many stacks, and a player 'will die. Kor'kron Shadowmages have a Mind Spike that can potentially one-shot players, while the Treasury Guards hit quite hard. The trash before Garrosh is also very difficult, particularly the slimes that heal ones nearby when they die.
To date, there is no enemy in Final Fantasy XI quite like the Soulflayer. For starters, unlike regular monsters, who take offense to your appearance, the sound of your feet on the grass, your particular odor, or perhaps the audacity with which you cast magic spells in their presence, the Soulflayer is a humorless dick and will assault you for performing any of the aforementioned actions. A Soulflayer would agro thoughts if technology permitted. If you want to avoid them, preventative measures like Sneak won't work and you won't be able to Sleep it if it does agro you. And if you happen to wander too close to a congregation of Soulflayers, the one you did agro will alert all the others via high-speed telepathy, potentially raining Soulflayers down on you en masse. Like other Black Mage-types in the game, it makes liberal use of area of effect spells (which are particularly devestating in XI due to player reliance on "blinking" individual directed attacks) and, arguably worse, a spell that causes players who strike it to become paralyzed. That wouldn't be so bad in and of itself, except that the processing rate is practically 100%, so unless you want to be completely useless against it, you will need to dispel that effect immediately... except that it's near-immune to Darkness-based spells, which includes, oh, hey, Dispel. And it only gets better. Among the plethora of abilities it has at its disposal, it can dispel all of your buffs, create magical shields to absorb magic damage, and bust open the Ark of the Covenant to inflict only the most impotence-inducing status effects known to man (and some unknown to man). And finally, they're gross. They even make squelching noises when they move. You just have to fear and loathe them and respect their status as the Queen Bitch monster of FFXI. Even the fact that there are light-based options for Sleep and Dispel doesn't take away from their status as Queen Bitch.
Wamouras. They heal thousands of HP just from being debuffed, drain all of your MP and go SSJ4 on a whim.
Apkallu can classify as this. At first, they're extremely weak, but as you kill them and build up "Apkallu Hate," their combat abilities grow exponentially, to the point that even an Even Match Apkallu will have almost capped Evasion/Guarding/Countering against you.
In the third expansion, "Treasures of Aht Urhgan", players were introduced to a breed of tiny bug enemies called Chigoes. Not only do these things do massive damage to you at a very quick rate, but they are nearly invisible until they're assaulting you. There is no name hovering over their head, nor are they targetable, until they begin to attack you. Your only defense is to keep an eye out for a little bouncing bug in the high grass you're walking through (though the spells Sneak and Invisible help). However, it should be noted that Chigoes are instant killed by any damage dealing job abilities (like a Dragoon's Jump or a Paladin's Shield Bash), or by critical hits, making them an uncommon sort of Glass Cannon. There's also one Sheep monster that spawns an infinite supply of Chigoes to pester players hunting it.
Speaking of invisible monsters, Yovras (affectionately dubbed "UFOs") are also nightmare-inducing. Their absolutely devestating arsenal of TP attacks is one thing, but what's even worse is the fact that they regen at rate of 100-250HP every 3 seconds. Before the level cap increase, their natural regen rate alone would often induce a stalemate against lowman groups farming them.
Even worse are the Lou Carcolh, introduced in the Wings of the Goddess Expansion. They have a special move which will UNEQUIP EVERY SINGLE PIECE OF ARMOR on you. This isn't all: the move prevents you from reequipping for a short duration, and applies a movement speed debuff so you can't run away. Only beastmasters used these as pets, and the pet mechanics meant if you ever lost charm, the mob would immediately turn to you and often use a random special move instantly. A good chance was that it used that move.
Many enemies in FFXI are demonic spiders of some form or another. Spider mobs can one-shot players with their Sickle Slash move. Corses can charm players: that made them impossible to straight tank, and if you soloed one with a pet and got charmed, you'd drop aggro and follow the mob around till charm dropped, often meaning certain death. A bomb's self-destruct can wipe out a whole party. There's a reason the game was nicknamed "Crab Fantasy XI"— crabs in the game are one of the few mobs that aren't demonic and are safe to level on.
Striped bumbaloons can vengeance strike anyone that hits them up to three times which makes it a chore to keep your Swashbuckler alive.
Frogerales are annoying at the Castillo Sapo dungeon, but at the Frogerale Warden, they can take down a level 50 swashbuckler with their constant spamming of overwatch. At the end of cool ranch, Bloody Bob Barnes appears on every ghost ship you fight and LOVES riposting your attacks. Especially problematic when you get cancelled out of an attack string with a companion like El Toro.
Mooshu gets even worse.
This time they have Samoorai Champions and Archers. Samoorai Champions get lots of free hits due to both first strike and vengeance strike. Samoorai Archers love pelting you with arrows and seeming to get a free bonus attack whether they hit or miss.
However, they don't even come close to Tengu Sorcerers. They can hit multiple targets with one attack, then spam the primary target with a string of mojo echo procs.
Marleybone has two particularly brutal ones.
Armada Dragoons. They love spamming The Big Guns half to death so you and a few companions are at about half health when you're playing with a 4-player group and you're focused down.
Radical Dogs. A minor one, but can beat you down by getting a relentless string. Especially problematic when they start beating down your musketeers.
Aquila has the most out of all of them.
Manticores. They can lock you in a relentless string just like radical dogs, but they are quite dodgy and can riposte attacks for bonus damage.
In the same vein as Armada Dragoons and Tengu Sorcerers are Saytrs and Ophidian Flame Dancers. They may cause some trouble when there's only one pirate, but a four player group is going to result in a bloodbath. This is especially true with Ophidian bosses like Mari and Chryssida.
Ragnarok Online has many versions of these on various maps. Each player has their own personal Demons depending on the class and the skills they pack.
Hunter Flies are perhaps the earliest example of the trope in RO; they're fast, they hit hard, they attack quickly, and they have crazy-high evasion, which made them pretty difficult even for experienced players. Their addition to level 1 of the Geffen Dungeon ruined that spot for many lowbies trying to level there, which was only made worse when the skill update gave them the ability to teleport.
For Mages, their personal nemeses are the Ridewords in the Clock Tower. Clock Tower is one of the best places for mages to level as the Fire Wall spell (one of the best defensive spells) can be put to good use against most of the enemies there. The Rideword is a possessed demon book that eats mages for breakfast. Not only is it generally fast enough to avoid firewall, but it has an annoying habit of spawning next to you while in the middle of fighting other monsters (usually in the middle of casting a spell, which leaves you helpless), can kill in one or two hits and has tons of HP.
For Full Support priests, who can only reliably deal damage to the undead, Mimics are the bane of existence. They're fast, attack for a moderate amount of damage (but fast), and often, if not always the only non-undead monster on maps populated with undead monsters. They give crap for exp or loot, and their high Flee makes them annoying to every class. So naturally, they populate just about every decent leveling map for middle-high levels. Woe be to any acolyte levelling alone who hasn't learned Teleport.
The Biolabs Ghosts are gargantuan pains in the tuchus. Superpowered, ghostly versions of the transcendent classes, they can and will use their respective job skills to utterly destroy you. Sniper Cecil can snipe you from far away, and Assassin Cross Eremes can sneak up and kill you before you even realize it. High Wizard Kathryne can spam you to oblivion and use area of effect attacks with little to no cast time required. Mastersmith Howard is just annoying because he can break your stuff, and Lord Knight Seyren has an attack that pretty much instakills you. As if that wasn't enough, all the Biolab ghosts are capable of quadrupling their attack power.
This would be pretty bad in a normal RPG, but since this is an MMORPG, they need ways to deal with multiple players. As such, each and every one of the Biolab Ghosts have an identicalboss version! The names are slightly different (example: Assassin Cross Eremes is the boss while Eremes Guile is the regular monster); they're crazy aggressive and they have a huge mob, usually containing a bunch of the other Biolab Ghosts.
Thankfully, the Biolabs Ghosts all exist in a dungeon which requires a quest to access (often a sign of extremely high difficulty), and they do have good loot, so you're able to kill one or more of them the loot is usually worth the frustration. However, their ability to be summoned by Dead Branches means poor beginners are likely to find them wandering around on low-level maps. And Bloody Branches just make it worse.
Other examples include Familiars and Drainliars (the bane of many a new player, since they hit quite hard and are fast, but end up becoming Goddamn Bats or easily-ignored mooks at higher levels), Wootan Fighters (super-powered apes in an otherwise tame jungle map) and Teddy Bears (about two-feet tall, super fast and wielding hammers in a dungeon with otherwise slow moving enemies). All of these monsters are just rare enough to not ward players away, but common enough that all players will eventually have one spawn right next to them while fighting the weaker monsters.
RO wasn't always this way. Maps used to be somewhat logically balanced in terms of monster types (and only led to early deaths if one wasn't familiar with how lethal butterflies can be). Things went downhill after the prerequisite Japan-themed maps update, in which the developers thought it'd be a great idea to change most of the older monster spawning locations. Thus, at least one Demonic Spider would be put into a great deal of (once) popular maps. Another patch would also finally give monsters the ability to use magic and skills, either toughening pre-existing Demonic Spiders or making new ones out of some of the older monsters. And of course, as expansion after expansion came out, the developers would add new species to make things more interesting.
A large part of the reason for most of these changes was due to the multitude of bot program users: bots allow people to speed level or farm items, and rampantly so at that. It proved relatively effective, too; few bot programs are capable of responding to changing situations.
Kingdom of Loathing has the Mine Crab, a crab with a sea mine on its back: they exist in the absolute hardest level in the game, have lots of hit points, do large amounts of damage, and if you hit them for more than 40 points of damage 'at all, they explode, killing you no matter what. They have lots of hit points and by the time you reach them, dealing less than 40 points of damage is a major problem. Oh, and if the battle runs too long you lose automatically.
Part of the design philosophy in Tabula Rasa. If it isn't immune to half of the available weapons types, it probably can heal and rez allies, or can make themselves invulnerable for periods of time, or reflect damage back at you. The real fun enemies combine these attributes: Atta are immune to electric, thermal, and virulent damage, have massive health bars, spawn in groups, and choose between an attack that ignores armor or an attack that knocks you on your backside at range. Linkers will, at random intervals, make themselves invulnerable to all forms of attack and reflect any attacks against them and unleash all the damage done to them again as they become vulnerable again; players can and regularly do commit suicide trying to plink them. Rakash Repair Bots heal themselves and allies, ignore armor, have locations where machines spit one out every eight seconds, and can create copies of themselves, their allies, or even the player.
The 1.5 patch made things worse; previously 'normal' troops that were only immune to a couple damage types now turn other bad guy corpses into chain reaction bombs, can throw off player accuracy, and/or suck players into a small area before unleashing artillery.
The MMORPG MapleStory has a large number of these depending on player level and class, such as Nependeaths, which auto-agg and spam with a similarly unavoidable ranged attack (but are mercifully immobile), Electrophants, which have no knockback and deal absurd amounts of damage, and Jr. Nekis, which are fast, absurdly difficult to hit, and deal an inordinate amount of damage.
Electrophants are particularly aggravating; they deal around 100 touch damage (which is tiny), and around 700 magic damage (which is lethal at the levels you would fight them at).
Runescape has the infamous Shadow Spiders. They aren't particularly damaging, but the minute one attacks you, it cuts your prayer points in half. When you consider that prayer points are used both to No Sell enemy attacks and give hefty buffs, you see why they're so dangerous, especially considering that Jagex loves to put these guys right at the start of several dungeons.
Revenants are demonic spiders themselves. They can attack you while you're already in combat with something else, freeze you, poison you, prevent you from teleporting, heal themselves, cure themselves of poison, and are overpowered for their combat level. The player killers they were meant to replace could do this too, but not all players could inflict the Standard Status Effects, and several are 50 times more powerful than a player of the same level. There are NO LEVEL 7 PLAYERS that can do 90 damage. Or freeze you. Or teleblock you. Or attack from beyond the draw distance(!!!), which is almost a guaranteed freeze or teleblock.
The good news is, Jagex shuffled them into their own specific area after reverting the wilderness and free trade changes made in 2007, meaning you can just ignore them entirely if you want to. The bad news is, Player Killers are back; Player Killers are notorious for using some of the same or comparable tactics; particularly, spells that keep you in place and teleblock spells. Made that much worse by the fact that other players can obviously run as fast as you, so unless you've got some manner of run energy regen at your disposal, you're screwed.
The Dungeon Spiders in Dungeoneering. They can poison you, which does 50 damage every 20 seconds or so, which fades away very very slowly. Within Daemonheim, every resource is limited, including food, so losing this much HP is a major issue. However, it's not just that. They can poison you through prayers, which you would expect to stop that sort of madness. Fortunately, there is a cure which can be bought for just 200 gp, and potions which give immunity for several minutes can be made with Herblore.
Brutes in Daemonheim. They're not as infuriating as the dungeon spiders, but their attacks are utterly devastating, especially at higher levels.
One of the challenge rooms in Dungeoneering is a bit of a Demonic Spiderweb. The Mercenary room is impossible to complete without racking up several deaths on a solo dungeon. On a members world, it might involve getting attacked from all three sides of the combat triangle at once by Tier 11 mercenaries.
There's also Shadows in The Temple of Light, from "Mourning's End, Pt 2". They do a huge amount of damage and interrupt you when you're trying to work That One Puzzle. Note that as part of the puzzle, you must bring up windows on-screen, and being attacked automatically closes those windows. Thankfully, they have pitiful HP and defense, but they respawn fast and will swarm you if you let them.
Goraks, extradimensional monsters that can ignore prayer, hit excessively hard, and drain your stats. They're only found in a couple places (God Wars Dungeon and the Gorak Plane), but they're extremely aggressive and can be dangerous if you don't have a quick means of escape or a way to raise your stats back up. Just to add to that, their drops mostly consist of low-level weapons and pitiful amounts of gold.
Everything on Ape Atoll, unless you're a monkey. The spiders and scorpions, despite being tiny, can easily smack you with nasty poison and respawn almost instantly after death. The monkeys come in packs and can deal ungodly damage, and the zombie and skeletal varieties in the gnome tunnel will mob you if you give them the chance.
The giant swamp snakes in Temple Trekking / Burgh De Rott Ramble. Not only do they have powerful, fast melee attacks, pack hefty HP, and come in packs, but unlike the other nasty monsters (shades, snails, ghasts, and nail beasts), they can't be easily distracted from your companion. When you enter the area for the event, you're almost guaranteed to get swarmed, with several of them focusing on your companion. If you don't have enough food in your companion, then you're screwed, and it can be outright impossible on the hard route.
How about an old one? In the older versions of Runescape, you had the Draynor Jail Guards. They were aggressive, located in a multicombat area, and were less than a minute away from Lumbridge, the starting town. They were the bane of many a new player.
The most memorable are the Cherry Fluffs. Nearly everybody has their favorite story about their first foray into Zen Gardens, seeing a Cherry Fluff, thinking "oh I eat these guys for breakfast", and then getting beat when the fluff they attack explodes for over 100 damage. It's not recommended to use area-of-effect attacks in Zen unless you're absolutely sure there are no Cherry Fluffs around.
Kokeshi Dolls are notorious for swarming (they're one of the earliest Animated to do so), especially if you're attacking their stronger Collectible form or Katsumi's Doll, and they have a ranged attack.
Taiko Drums, also in Zen, pack area-of-effect attacks and have attacks that knock the player around.
The Flying Giftboxes regenerate.
Sand Fluffs in the Gold Beach area will sink you in quicksand, slowing you while they gather around to chip away your HP. You need ranged attacks to fight the Sand Fluffs or quickly scroll to a new screen away from them.
The Predator Prarie Pups turn invisible when they attack. It helps to keep a finger on the tilde (~) so you can auto-target them, especially if you're in one of the foresty screens where they can hide behind trees.
Tiny Witch Doctors in the Otami Ruins have a slowing attack. It doesn't help that they're usually accompanied by mobs of Tiny Terrors.
The Mask of Death and Rebirth's most powerful attack also stops you dead in your tracks. It also appears out of nowhere if you're on certain flights of stairs, and gets progressively stronger as you knock off each of its three forms. In its last form, its attack will a) force your avatar to run away, b) disable the use of your rings, and c) only wear off after a certain period of time, which is still long enough for the Mask or other enemies to strip you of your HP.
Walkers have high HP and defenses and can either use a powerful melee attack or a ranged attack that inflicts poison. Also, they tend to come in groups. Landstriders are rarer and weaker, but still a pain.
The dungeon Shards of Orr from Guild Wars expansion Eye of the North, is plagued with these, from mobs consisting of zombie brutes who deal lots of damage, coupled with skeleton sorcerers who blind you and knock you down, and then add a cleric to the mix for healing them, oh and for the record: groups of many enchanted weapons that are all agroed at the same time.
And from the third game, Nightfall, you have the Torment Creatures. The fact that they come from Hell demands they be tough, and while they certainly are, they ALL come equipped with a defense mechanism guaranteed to make you grind your teeth. When a Torment Creature is almost dead (although sometimes they've been observed doing this as high as 40% health), it crouches down and you have EXACTLY ten seconds to kill it before a duplicate spawns in. The duplicate? IT HAS THE SAME SKILL. The worst ones by far are the Arms of Insanity, rangers who, before activating the ability, will use two different preparations that a) give them roughly eight pips of regenerating health, and b) enable them to dodge 75% of your attacks. Without careful micromanagement in most situations, you can go from fighting five of them to fifteen in an instant.
Any enemy with a resurrection spell can quickly become this. Charr Dominators can not only disable your abilities if you're unlucky enough, but their fast casting attribute lets them bring enemies to life in about half the time your team can (although that's because they were actually based on a popular human build). And Awakened Cavaliers come with both one of the fast-recharging resurrection signets AND a shout (as in instantly-activating) that brings all their teammates back. Logic demands you eliminate these sorts first, but you'll more often than not cross a group where more than one of them are present, sometimes also backing a boss. The best response to the resurrection ability is to lay down the "Frozen Soil" effect. It prevents any resurrection spell being used in the affected area. Only problem is that that includes your resurrection spells too.
In the first campaign the wandering Hydras of the Crystal Desert could easily become this. While their damage output usually wasn't bad, their AI tended to wait until you group up and then all of the Hydras would cast "Meteor". Three Meteors could kill a group, and guess what the standard number of Hydras in a group is.
The White Mantle and Peacekeepers of Beyond: War in Kryta can easily become this. Each class can have one of several different skill sets, making predicting which ones in a pull are the real danger difficult. The monk might be a heal, but it could also be a dps; the elementalist might be a spiker or it might have area spells; and any single one of them could have a spell that resurrects any dead ally at full health. Some of their builds actually seem to be inspired to power-gamers, just for that extra bit of insult to the many injuries.
Continued in a similar manner in the Winds of Change by the new enemies of Cantha. The modified zones are such a change in difficulty that the developers eventually added an option to switch back to the days when it was overrun by a mystical plague.
Star Trek Online: The Borg. Not the weak, disjointed, disconnected past-version Borg from the tutorial, but the full-on modern Borg from the endgame area. On the ground, they will keep summoning more, and more, and more, and more, and 'aaaaaaagh'. In space, they will quickly render you helpless and then pound on you; like the the TV series, Borg Cubes fire shield-draining torpedoes at you, and no amount of shield recharge powers you have on hand will keep your shields from collapsing and staying down until the fight is over. This necessitates the use of armor plating. Without it, you will die. One Borg Cube will provide a long yet not impossible fight on your hands. Two Cubes are virtually impossible to defeat solo. "Resistance Is Futile" indeed.
Fittingly, the Borg's main enemy, Species 8472/Undine, also fits this trope. In the final ground mission released to date, the player ends up fighting through large numbers of Undine soldiers, which are, like the Borg, not at all similar to the weaker versions that can be found earlier in the game. These ones hit you non-stop, both with melee attacks (which can cause a nasty infection, due to 8472's superb immune system) and with ranged psychic attacks. Both of which ignore shields, the melee attacks mostly penetrating and the psychic attacks avoiding shields entirely. There is one type of Personal Shield in the game that will block some psionic damage, which is found as a mission reward at the start of the Featured Episode arc involving the Devidians, but it was given so much earlier in the storyline that odds are you threw it out as it became obsolete. Since drops increase in level as you do, you have the option to go back and pick up a stronger, level-appropriate version, which makes the mission a good deal easier. However, 99% of players at this point will be using a personal shield more geared towards fighting the Borg or engaging in PvP combat, which makes every single enemy in the mission one of these.
Spiral Knights has plenty of stuff waiting to ruin your daynote and ways to counter. Usually one monster per enemy type:
Beasts have Alpha Wolvers. They inherit the normal Wolver trait of dodging guns and their Flash Step into melee, but now buff any small wolvers in the area, are near impervious to being knocked down, and do a three bite combo that will break shields if blocked entirely. In later tiers they gain Teleport Spam.note Attack them when they yip, have teammates attack from the side during the combo, or hit them with the Faust or a curse vial, since curse will trigger thrice during their combo.
Constructs have Gun Puppies. Although immobile, they tend to camp areas that are hard to reach when they spawn, thin paths filled with spikes, or spawn up to 8 at once in the arenas. They have the highest bullet count of all enemies, meaning that any encounter with more than two can turn into Bullet Hell in a hurry.note Not very hard to stream their shots and gun them down. Also easy to bait with one player shielding, and the Cailbur line's charged attack can hit 3 times. The arena Zerg Rush is always brutal, though.
Even tougher than Gun Puppies are Rocket Puppies. On Tier One they shoot an easy-to-dodge missile. Tier Two makes adds a light homing function. Tier Three? High-speed missiles! Homing on a level barely dodgeable! They are not destroyed by obstacles! They do more damage than almost any other enemy of the same level! The explosion inflicts burn status which unblockably chips away your health you even further! Missiles destroy your shield in one or two hit! It fires almost fast enough to keep a missile on the field at all times! Similar to Gun Puppies above, you can face eight of these in an Arena match! Whew!note The missiles can hit other enemies, use this to your advantage. Don't aggro too many at once. Make sure your combo makes the turret abandon its attack if just possible.
Fiends are annoying in general, but late-strata Greavers can be deadly. Greavers can Flash Step into a melee attack that leaves behind an unblockable status cloud. And they have a habit of swarming the player.note Melee knocks them out of their attack entirely. Someone with a Flourish can tear up Greavers with ease. Make sure they don't swerve around you when you strike, though.
Gremlins are another annoying monster type in general, but demos are the greatest pain in the ass. At their tier 1 form, they're merely annoying, but tier 2 brings the bomb spam like none other. They spam mines and dodges making it impossible to safely attack them most of the time, and will often toss four mines at a player, which proceed to land on the ground and arm themselves when they hit. And then when you do hit them, a mine will often fall from their backpack... which promptly arms itself when it hits the floor. And to top it off, if damaged and left alone they will pull out a health capsule and recover a bunch of life. The mines not only act as very effective space control, but they also make for effective anti-freeze.note They aren't very aggressive and the mine fuse is easily visible, so charged attacks work nicely. Also, a decent gun can chip away their health.
Phantoms are this of the graveyard themed Undead levels. Far-reaching three-hit combo, decent health and a projectile-firing charged attack are far from unbearable... But the damn things don't give up. When you kill them, they come back in a few minutes. When soloing, they're easy to deal with, but there's one for each player - in four-player expeditions you are stalked by four of these which can be overwhelming.note Phantoms aggro their designated player. Either have the person in question deal with the opponent solo, or gang up on the Phantom while the target acts as a diversion. If you have a gun you can use while mobile, you can just back up and keep firing.
A weird example, Need for Speed: World has Demonic Spiders in the form of Rhino SUVs, which usually come in packs of two and try to ram you head-on. For balancing reasons, EA Black Box has made getting busted in a pursuit much easier (the speeds required to start draining your Busted meter has been increased greatly), and a single Rhino charge will bring your car to a dead stop instantly, regardless of how fast or heavy it is. Rhinos are incessantly annoying at lower heats (with space, they're easy to dodge), but they become extremely deadly at heat 5, where loads and loads of roadblocks will impede your practical top speeds and Rhinos come in every thirty seconds. If a Rhino scores a direct hit, using powerups to escape is essentially a prerequisite.
In La Tale, there are wisps, which follow you around and not only damage you constantly and over time, but they also drain your SP. Wisps also have a lot of health. God help you if three or four attack you at once. Granted, they DO give you a ton of experience points, but still...
Listing all the Demonic SpidersThe Old Republic has would take it's own planet segmented page to fill, so it's far easier to point out certain Demonic Ability's (that many, many different mobs share).
Any type of passive bleeding/burning buff makes any strong or harder enemy eye gougingly annoying. These abilities are up all the time, stack every single hit (it's impossible to avoid if facing a ranged enemy), do ridiculous amounts of damage, can't be interrupted (and this game has no enemy dispelling), and since they refresh every hit as well, are basically there until you kill whatever is setting you ablaze. To make maters even worse these types of abilities always come on something that is built like one of the PC tanking classes, meaning that there is no way you are going to be able to kill one before you've lost half your skin or blood.
Certain boss elite enemies come packing some sort force storm abilities. These pack one hell of a wallop, and leave the boss to continue attacking while the AOE is still going. The problem is the animation just doesn't do them justice, the actual AOE is far bigger than what you can see and lasts longer. Not to mention that the boss can just stand in it, making it a catch 22 for Melee characters who need to interrupt the massive 2 hit kill ability he is surly casting while being surrounded by electric death.
A really common AOE mobs have involves sending a small droid down that shoots fire everywhere, doing massive damage. However it's easy to avoid, stationary, and usually has a tiny radius, but companions will not get out of it unless you specificity tell them too. Meaning that either you let them attack and quickly die or try to keep him safe wasting time and both of your dps, all the while the deployer and his buddies are filling you full of holes.
Dungeons & Dragons Online has most spellcaster creatures become this at the very least when completing adventures of Hard or Elite difficulty, able to spam lightning spells that do as much damage as high level abilities used by boss creatures. Regular enemies that are this are Rust Monsters and Oozes, which in addition to causing acid based damage to your character (requires a special resistance in addition to normal Armor Class), they deteriorate your weapons and armor. Fire elementals can be like this too, if they're anywhere near a source of heat since it recharges their health.
Ak'ab in The Secret World. a combination of a charge attack that stuns, and the tendency to move around a lot, means players can be fighting large groups of these at once, and be stunned for large amounts of time in that fight, if not careful.
Star Wars: Galaxies had the Nightsisters of Dathomir. They were extremely powerful on the attack (able to kill an unbuffed player in a few hits), had oodles of HP, were resistant (or, in the case of the higher level ones, completely immune) to most types of attacks and, unlike other dangerous pieces of Dathomir's wildlife (like the Rancors), were not easily spotted thanks to their drab garb and relatively small size. Oh, and the best part? They attacked vehicles and would usually destroy them in a single attack, meaning you could be flying across the wilds on a speederbike, only to have a nearby Nightsister blast it out from underneath you and then proceed to turn you into pocket mulch. Nightsisters were the reason why no one dared take out rare vehicles - like AV-21s - on Dathomir until the game was updated to allow destroyed vehicles to be repaired.