One of the games I'm currently running has some seriously overpowered characters in it, and I've found that in the last few sessions I've not done a very good job of challenging them. So, recently, I constructed an adventure which was entirely combat oriented, and filled with custom monsters designed to bypass many of their ridiculous defenses. I wanted something really special for the final encounter of the session, so I made up the monster which is detailed below. I've done a lot of work since the game to polish it up and make it available for Pathfinder GMs.
For the record, the game went pretty well, except the monster below ended up being too much for them. The sorcerer got reduced to -13 HP (dead) after just a few rounds, and the Dawnblade (homebrew variant of the Duskblade) character got reduced to exactly 0 when the beast still had about 50 HP. Fortunately there's a super-secret reason why this particular monster was unable to kill that particular character...but it's still out there.
The name isn't just a jumble of letters, by the way. I noticed after the fact that the monster bore a kind of resemblance to a little-known creature of myth.
Corpse Sewn HekatonkheiresEight "tentacles" made of severed human arms--each holding tightly to the stump of the next--wave about the body of this horrifying undead. Its bulbous body is a throbbing sack of vein covered flesh, almost like a massive heart. And, on the end of the pulsating monstrosity, are fifty human heads. Each has rotted away to a sagging gray mess, which stares with white, hungry orbs.
Corpse Sewn Hekatonkheires; CR 14; [Undead] [Swamp] [Temperate Climate]
NE Huge Undead
Init +4; Senses darkvision 60ft; Perception +20
AC 8, touch 8, flat-footed 8 [10 + Dex(0) + Size(-2)]
HP 300 (16d8 + 238)
Fort +5 Ref +5 Will +5
Speed 40-60ft.(See Text); swim 20ft. (Can run 5 at times normal speed)
Melee 2 or 8 tentacle slam attacks + 17 (2d8 + 7)
Space 15ft; Reach 10ft.
Special Attacks Breath Weapon (60ft. cone, DC 20, 12D6 acid)
Str 25 Dex 10 Con -- Int 2 Wis 7 Cha 38
Base Attack +12 CMB +21 CMD 31 (Can't be tripped)
Feats Toughness, Improved Initiative, Multiattack, Improved Natural Attack, Awesome Blow, Ability Focus (Breath Weapon), Ability Focus (Hungry Heads), Alertness, Run
Skills Climb +16, Perception +20, Stealth +16, Swim +16
Environment temperate marshes, riverbeds, small lakes
Awesome Blow(Ex) As a standard action, the Corpse Sewn Hekatonkheires may perform an awesome blow combat maneuver. If the maneuver succeeds against a corporeal opponent smaller than the beast, its opponent takes 2d8 + 7 slam attack damage, and is knocked flying 10 feet in a direction of the Corpse Sewn Hekatonkheires choice and falls prone. The attack can only push the opponent in a straight line, and the opponent can't move closer to the attacker than the square it started in. If an obstacle prevents completion of the opponent's move, the opponent and the obstacle each take 1d6 points of damage, and the opponent is knocked pron in the space adjacent to the obstacle.
Hungry, Hungry Heads(Ex) Any character which stands in a square adjacent to the Corpse Sewn Hekatonkheires' 50 heads is subject to a bite attack. This is an immediate action for the Corpse Sewn Hekatonkheires. Characters are allowed a DC 20 [10 + 1/2 HD(8) + Ability Focus(2)] to avoid this attack. If the save fails, roll 2d6 to determine the number of heads which successfully bite the character. Each bite attack deals 1d4 damage.
Breath Weapon(Su) Using a breath weapon is a standard action. A Corpse Swen Hekatonkheires can use its breath weapon once every 1d4 rounds. A breath weapon always starts at an intersection adjacent to the beast and extends in the direction the creature's heads are facing. Those caught in the area can attempt Reflex saves to take half damage. The save DC is 10 + 1/2 the monster's HD (8) + the monster's Con modifier (0 for undead) + the Ability Focus feat (2).
Tentacles, Attacks, and Movement The Corpse Sewn Hekatonkheires has a relatively light body considering its size, which allows it to walk on its 8 tentacles. Lifting itself from a position resting on the ground or in the water, to a "standing" position requires all 8 tentacles to be engaged in a standard action. Once standing, the creature requires only 6 of its tentacles to remain standing, and may attack with the remaining two. When support itself on 6 tentacles, the creature can move at a land speed of 40ft. When using all 8 tentacles to support itself, the Corpse Sewn Hekatonkheires can move at a speed of 60ft. Shifting between using 6 tentacles and 8 tentacles to support itself is a move-equivalent action.
Background The Corpse Sewn Hekatonkheires is the creation either of an extremely masterful, or extremely foolish necromancer. Animating the creature requires a hundred human bodies, but many power hungry casters view the requirement as worthwhile due to the beast's expertise in keeping troublesome adventurers from getting through the swamps surrounding a necromancer's headquarters.
These amphibious monstrosities typically hunt near shallow water. Often they hide under a bridge or other river crossing, camouflaging themselves as piles of muck, and make their first strike as soon as no one is looking.