For my money... it's gotta be Giants, and to a lesser extent Elementals. I just can never really come up with a satisfying way to fit them into the world.

Giants work best in their own world. You can't hardly have a dungeon with a bunch of other monsters in it...and giants. On the other hand, Against the Giants showed that they make much more sense when they're in their own stockades and fortresses, and everything is scaled to them, rather than when they're forced to fit into an otherwise human-scaled dungeon.

Elementals aren't really part of this world, the only way ther're supposed to be used is as summons or aberrant appearances.

AD&D Intellect Devourers do it to me. Seriously, almost impossible to hit or harm significantly, and enough abilities to get a character alone and slaughter him, practically no save.

I get what the concept intends, but it's really tough to make the model work as intended.

The Chronicles of Thomas Covenant use giants quite well I thought. Far away from human settlements for the most part. The trolls and mountain giants in the Hobbit were also pretty good. Oh and of course the giants from Game of Thrones.

I'm not sure about monsters I can't fit in, but I always had trouble taking beholders seriously. Krang from the TMNT is all I hear, hyuhhuhyuhubbleurgh.

Yeah, either "A" giant, or a bunch of giants but by themselves maybe with a few servitor monsters (like in the G series).

For me it's Intellect Devourers.  Scary looking (well, I think they're scary looking - brains on legs yeeg), scary description...aaand absolutely no threat to anyone who isn't a psionic.

Flumphs.

I've never really come up with anything engaging to do with mummies.

I like integrating giants into "evil hordes", aka its not uncommon for a hill giant to show up and declare rulership over a bunch of orcs or goblins, just to have slaves.

I agree with Mummies being challenging. They are common enough in tomb scenarios, but often come off just as high level zombies.

I rewrote the Intellect Devourer into something that messes with anything with intelligence, not just psionic beings. In my OD&D games, the beastie has an 5 foot (close range) aura that drains 1 point of INT and 1 point of WIS each round and its tactic is to pounce on a foe, hold it down and eat its thoughts and memories until the victim is comatose...leaving the meat body for another creature to feast upon.

Those centaur - lizard things from Warhammer. Also, dragonogres (Ogredragons? Hells if I remember the proper spelling) - a good example that sometimes, something that ought to be at least cool (it's ogres AND dragon AND it eats lightning!), isn't because it's just one gimmick too many.

On that note - Games Workshop certainly didn't know what to do with Fimirs, and FOR SHAME, because they are one of the more clever, dangerous and creepy antagonists (a tribe of swamp creatures that summon fog and constantly capture human/elven women for their unholy offspring? Come on).

Quote from: Rincewind1;643875Those centaur - lizard things from Warhammer.

The Zoats? Ha! Yes, I thought they were awesome but never really had much use for them. I kept expecting some kind of supplement to give us more information on them, figured they'd make a great alternative PC race, but they got written out of WH continuity before that happened. As it is, they just get a paragraph in the beastiary alluding to them being in some way descended from the Slann, and users of powerful magics never described.

Quote from: thedungeondelver;643843For me it's Intellect Devourers.  Scary looking (well, I think they're scary looking - brains on legs yeeg), scary description...aaand absolutely no threat to anyone who isn't a psionic.

Well, they need to be changed to make them a threat. Use Fiend Without a Face (1958) as a guideline (I swear, that's where the idea must have come from...) Psionics (or spells that have to do with thought, mind, or illusion) attract them, but they feed on anything intelligent.

I think for me, most of the monsters are potentially usable, at least as one-offs. I don't like the idea of monsters as species, anyways. The ones I have trouble using are the ones that seem incoherent or just ridiculous. Stuff with random body structure that seems to have no connection to its behavior, and random abilities or defenses.

I'll probably get into a cannon flame war with Warhammer fans but Dragon Ogres were originally Zoats and were corrupted by chaos before the coming of the Slann.

The thing about Dragon Ogres is that they're world weary immortal killing machines.  In one game I had one show up on a battle field only to be challenged by a zoat.  They fought to the death while lightning rained down from the heavens on them and the Empire and Chaos Maurauder forces withdrew in awe and horror.  After the Dragon Ogre expired (to be fair it had caught a couple cannonballs before the Zoat showed up) the PCs who were hiding in the woods wound up being close enough to hear it speaking sorrowfully to itself as it slipped away "Oh my brother, what have you done to yourself and our world?"

Ah well, for me the hardest monsters to do well and make work have to be slimes oozes and jellies.  They're just kinda dull.

Leprechauns.
They just slow my games down with absurdity. They just.... elude me.

Quote from: LibraryLass;643786For my money... it's gotta be Giants, and to a lesser extent Elementals. I just can never really come up with a satisfying way to fit them into the world.

I like having the Giants be a precursor civilization, as in, sometime after the downfall of the "HPL" type beings but maybe roughly at the same time as the dragons, elves (well, maybe after the dragons but before the elves...) and so on were really powerful, the Giants ruled great big empires. One idea I've had for years is to have at least one human civilization in my setting be the descendants of humans enslaved by the Giants (who rebelled and stole tech and magic from the Giants, natch).

In the actual gameplay, though, I tend to use Giants as packs of big dangerous humanoid-shaped warriors my players' dudes can fight & kill when ogres become too wimpy to be a threat save in huge hordes (Giants are less irritating than Trolls imo)...

I've used outta-control fire elementals trying to burn the world!!! as a plot point, and also used earth elementals as tomb guardians.

Quote from: David JohansenAh well, for me the hardest monsters to do well and make work have to be slimes oozes and jellies. They're just kinda dull.

I want at least a couple mid-level "Lovecraftian" caves inhabited by slimes/oozes/jellies in the campaign I'm working on. At least, dungeon levels dominated by the things.

Personally I just could never bring myself to use the MODRON from AD&D 1E MM2 book from the plane of Nirvana, I tried to write up a few scenarios once but each time it fell apart as I just couldn't come to grips with their strange appearances, looking like 2x4's balls, cubes and a pyramid and other weird shapes.  They looked as though they would fit better in a Sci-Fi universe than a Fantasy setting. IMO

Quote from: thedungeondelver;643843For me it's Intellect Devourers.  Scary looking (well, I think they're scary looking - brains on legs yeeg), scary description...aaand absolutely no threat to anyone who isn't a psionic.

On the plus side though, chances are that someone will bring cheese popcorn to the game and you have ready made miniatures.