A few weeks back I customized an elder black pudding by adding a fiendish template. The PCs in my campaign ended up not encountering it. Which is too bad. I had a ton of little counters made up in case they managed to split it into multiple oozes.
I probably skimped on messing with the skills and feats and whatnot when I made this, so it may not be 100% according to Hoyle.
Fiendish Elder Black Pudding
Gargantuan Ooze (extraplanar)
Hit Dice: 20d10+180 (380 hp)
Speed: 20 ft. (4 squares), climb 20 ft.
Armor Class: 1 (–4 size, –5 Dex), touch 1, flat-footed 1
Base Attack/Grapple: +15/+35
Attack: Slam +19 melee (3d6+12 plus 3d6 acid)
Full Attack: Slam +19 melee (3d6+12 plus 3d6 acid)
Space/Reach: 20 ft./20 ft.
Special Attacks: Acid, constrict 2d8+12 plus 2d6 acid, improved grab
Special Qualities: Blindsight 60 ft., split, ooze traits, Darkvision 60’, Damage Reduction 10/Magic, Cold & Fire Resistance 10, Spell Resistance 25
Saves: Fort +15, Ref +1, Will +1
Abilities: Str 26, Dex 1, Con 28, Int 3, Wis 1, Cha 1
Skills: Climb +16
Environment: Any evil-aligned plane.
Challenge Rating: 14
Alignment: Always evil (any).
Level Adjustment: —
The most ancient black puddings are vast pools of inky death.
A black pudding attacks by grabbing and squeezing their prey.
Acid (Ex): The creature secretes a digestive acid that dissolves organic material and metal quickly, but does not affect stone. Any melee hit or constrict attack deals acid damage, and the opponent’s armor and clothing dissolve and become useless immediately unless they succeed on DC 29 Reflex saves. A metal or wooden weapon that strikes a black pudding also dissolves immediately unless it succeeds on a DC 29 Reflex save. The save DCs are Constitution-based.
The pudding’s acidic touch deals 21 points of damage per round to wooden or metal objects, but the ooze must remain in contact with the object for 1 full round to deal this damage.
Constrict (Ex): A black pudding deals automatic slam and acid damage with a successful grapple check. The opponent’s clothing and armor take a –4 penalty on Reflex saves against the acid.
Improved Grab (Ex): To use this ability, a black pudding must hit with its slam attack. It can then attempt to start a grapple as a free action without provoking an attack of opportunity. If it wins the grapple check, it establishes a hold and can constrict.
Smite Good (Su): Once per day the creature can make a normal melee attack to deal extra damage equal to its HD total (maximum of +20) against a good foe.
Split (Ex): Slashing and piercing weapons deal no damage to a black pudding. Instead the creature splits into two identical puddings, each with half of the original’s current hit points (round down). A pudding with 10 hit points or less cannot be further split and dies if reduced to 0 hit points.
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