Strong Monsters

[Fishbone]

I was just wondering, what monsters in your experience have turned out to be stronger than first expected? To keep the post short I'll name one that surprised me: The Noble Salamander.
Good attack sequence, decent damage, and is very strong if you add a level of Fighter. The extra hit points and 2 feats really put it over the top. Not to mention that it brings a Huge Fire Elemental to the party.

 

[Victim]

The Tendriculous. Good attacks, lots of immunities from being a plant, fast regen, and Imp Grab. Their low speed is their main weakness, but that just means it's easy to flee from their power.

 

[Fishbone]

At CR 10 they can have a mondo grapple check and paralyze somebody for multiple rounds.
Boneclaws: At CR 6 they have over 150 HP, which is great for an undead, along with 20 foot reach. Maybe this thread could be titled "Underrated Monsters".
Kobolds. Hmm, CR=NPC Level -4 equals guys with 5 hit dice in the 1 slot. An archer or crossbowmen does little damage but you can have a king hell of a lot of kobolds for a low CR. They hit a lot, too. What will really shock the other players is the abuse a kobold can take. 30 hit points for a CR(max hit points for first HD, 14 for the constitution) will shock people who are used to kobolds just falling over if you breathe on them heavy.

 

[Kwitchit]

Digester. That acid attack will be doing some serious damage for a CR6, and its speed lets it be where it wants not where the PCs want. In 1d4 rounds it can kill the rogue and the wizard, and its speed means sneak attacks are unlikely.

Cockatrice. Very annoying when the PCs are too poor to pay for a Break Enchantment and too low-level to cast one. Plus they have to lug the stone statue around.

Adamantine Clockwork Horror. CR9 with an MDJ effect. Cause of strangled DMs everywhere.

 

[Staffan]

Psionic mindflayers. Replacing most of their fixed spell-like abilities with the abilities of a 9th level psion makes them a hell of a lot more powerful. 9d10 (will negates) mind thrust, +8 armor bonus to AC (inertial armor), and 3d4 Cha-damage ego whip are just some of the advantages they gain. Add a level of monk (with Improved Grapple, not Stunning Fist), and use their 9 HD feat to take Expanded Knowledge (Grip of Iron - lets them boost their grapple check by 8), and they become WAY too fearsome for CR 9 (base 8 + 1 monk level)

 

[Ditch]

Adamantine Clockwork Horror. CR9 with an MDJ effect. Cause of strangled DMs everywhere.

ROFL

There are lots of simple creatures that I feel are very powerful vs. the typical party that incounters them.

1st-2nd level parties hate:
Wights - level drains when you are 1st level are the suck
Vampire spawns - same as above + charm + CON drain~
I won't even bother stating the obvious immunities, etc.

At higher levels I think a mummy (especially multiples in a single encounter) is absolutely brutal. Not even considering their DR, fear, insane strength and all, they just plain make it a pain for the cleric to do any healing.

I agree with the above post about the tendriculous. But then I dislike any creature that can swallow me.

Ropers with their very long reach and insane SR are pretty tough. Their STR damage can potentially shut down any melee threats.

 

[Corbert]

I added the Effigy template from Complete Arcane to a Girallon and a Giant Constrictor Snake (raising both to CR 6) and sicced them on a party of 3 gestalt characters. A Paladin/Sorceror 7, a Cleric/Mage 8 and a Rogue/Fighter 8. The party got their butts practically handed to them until they ran

 

[Fishbone]

Ambush Drakes can be a real handful.
Try a CR 10-11 with 3 CR 7 ambush drakes. The main ambush drake will have a Slow breath weapon that it can belch in a 30 foot cone. With a feat like Ability Focus it can have a DC 24 Slow effect that lasts for 15 rounds then bring in the hounds to breath/bite.
Aboleths can be pretty nasty, and their Skum and Umber Hulk hordes aren't to be laughed at either. I think they're just as brutal as Mind Flayers.
Cloakers with moan are just bad but the Cloaker Lord in Monsters of Faerun is just so over the top. 9d8, tons of great abilities, casts as a 9th level wizard...
CR 7. Not a chance in Tartarus my friends is that a CR 7.

 

[Jubilee]

A nest of shocker lizards that you think are sooo cute and you wander into the middle of them before you finally succeed at your bardic knowledge to know you're in trouble because they all just ganged up on you and zapped you.

A cave full of tiny lizards? What could possibly go wrong?