
Gilarius |

Umber Hulks. Whilst not actually/officially in Pathfinder, there is a conversion of them available.
Basic idea: big, strong, melee brutes with 3 attacks per round (claw, claw, bite). Plus confusion spell as a gaze attack every few rounds.
Perfect opponents. Melee types tend to fail their will checks and casters would die quick if forced into combat with them.
6 sentences, plus this bit ;)

Kayerloth |
A few favorites from past campaigns:
- Shambling Mounds and any other creature that uses electrical attacks (Will O Wisp for instance)
- Iron Golems and fire/fire creatures
- Mimics pretending to be things other than treasure chests ... such as a row boat/ferry across an underground lake
- Mummies and brown mold
- Beholders and any otherwise safe flooring over deadly things like magma (Disintegrate the floor and ouch)
- invisible Rust Monsters (bonus if anything makes ranged engagement tricky or near impossible)
- Hag covens (levels in caster class(es) a plus)
- Aquatic Trolls in water filled rooms/environments

WPharolin |

Add an interesting mount and suddenly the boring becomes cool again. Next time your picking out a monster or npc ask yourself if it could be riding a cool mount. That wight cleric becomes a lot more memorable when he strolls in atop a dire bear. My most recent bbeg was a wingless balor named Ur that rides around on a celestial elephant.

Neo2151 |

Devils are my absolute favorite. The toolbox you have available as a GM is practically unlimited if you pull your baddies outta the 9 Hells (melee attacks, natural attacks, spells, spell-like abilities, good resistances, and they tend to be WAY more cunning than Demons so you can have way more ways to mess with a group than just combat.)
2nd place is Fey. I just find them interesting, no particular reason other than that.

Katya |

Lots of great ideas, thanks guys!
I had another friend suggest a Gold Dragon. Since they are almost always LG, it could be an interesting twist to the game when its revealed that the benevolent quest giver has actually be using the party the whole time.
Other suggestions in a similar vein were:
- an albino red dragon that is mistaken for a white dragon
- two warring beholders who lead a thieves guild and a temple. The players get caught up in what appears to be a divine battle against a group of sinners, but what is actually a battle of egos.

MagusJanus |

According to every 3E group I played with, my favorite was the Tarrasque. It tended to get unleashed by one of my characters. A lot. Though, my character did put it to good use once by using a Wish spell to unleash the Tarrasque on Vecna. Considering Vecna was one step away from ending all life on the planet, the Tarrasque couldn't make things worse.
My favorite is actually the deinonychus. I've been known to have them pop up in random places, sometimes behind closed doors... and, sometimes, those were doors the PCs closed earlier after confirming the room was empty. It gets fun when you start adding on class levels...

Katya |

So after reading through these posts and sorting through suggestions from friends, I think I've settled on:
- A thieves guild which is run by a cult dedicated to a hydra. The party begins to discover the cult's deeper mysteries as townsfolk start to get sick from eating bad eggs. Some of the patients die as juvenile hydras burst from their bodies (think Alien).
- An Illithid that toys with the party at several stages during the campaign before finally forcing a full confrontation when the party breaks up his slaver-driven food train.
- A cabal of mimics that operate an shipping and smuggling ring. The mimics take legitimate and illegitimate cargo, swap themselves in for the goods, then collect money on delivery. Once the cabal has been paid, the "goods" vanish. The party is tipped off after a series of grisly murders in the docks and warehouse district and a rare and powerful artefact fails to arrive at a local museum.
- A set out outlaying villages are gripped in what seems to be an series of unseasonal winter storms and sightings of a white dragon have piqued the PCs interest. They come to discover that the winter storms are being caused by a group of secretive druids in an effort to protect the villages from what is actually an albino red dragon.
- The feud between two temples spills over into the streets of the PCs' city as the head clerics of each faction begin to summon outsiders to do their fighting. The city is gripped by a blood war between a horde of demons and an army of devils.

insaneogeddon |
I'm in the very early stages of campaign planning and I'm soliciting ideas for baddies. I want to get outside of my own box here so I'm asking for what people like to fight / like to throw at their own players.
Please limit responses to 1 sentence, no stories or background required.
All these make for WTF surprises and are memorable/amusing/icky/code browns
Seugathi
Ettin
Stirge
Giant Tick/Tick Swarm
Shadows
Crocodiles
Boggard
Spriggan
Thunderbird
Shark Eating Crab
Disenchanter
Shadow Demon (possessing something)
Flumph
Globster
Skunk
Troll Hound
Redcap

Sealbreaker |

I am personally partial to the Worm that Walks. Full spellcaster, odd immunities and is really awkward to fight.
I have also found that awkward encounters tend to be harder and more memorable than just a monster with lots of hit points and damage. Flying, teleporting, fast moving enemies with strange special abilities and immunities are good fun.
Antipaladin mounted on drake doing flyby attack maybe?