In fluff, we're saying it's a half-hellwyrm gelatinous cube. Mechanically, it's a sentry ooze gelatinous cube with half-brass dragon and half-fiend. Please correct me if I've done anything wrong with applying the templates.
NE Gargantuan outsider (augmented ooze) CR ?? (14 right now)
Init 0; Senses blindsight 60 ft, darkvision 60 ft
Listen +X, Spot +X
AC 15, touch 6, flat-footed 15 (–4 size, +9 natural)
hp 379 (23 HD); DR 10/magic
SR 33
Immune electricity, fire, poison, sleep and paralysis effects
Resist acid 10, cold 10, electricity 10, fire 10
Fort +25, Ref +13, Will +13 (+17 against mind-affecting)
Speed 15 ft., fly 30 ft (average)
Melee 2 claws +33 (2d6+10 plus 1d6 acid), bite +33 (2d8+10 plus 1d6 acid), slam +33 (2d6+10 plus 1d6 acid)
Space 20 ft.; Reach 20 ft.
Base Atk +23; Grp +45
Atk Options Acid, breath weapon (6d8 fire, 60' line, DC 33 Ref for half) 1/day, engulf, paralysis
Spell-like Abilities (CL 23rd, saves Cha based):
3/day - Darkness, poison, unholy aura
1/day - Blasphemy, contagion, desecrate, destruction, horrid wilting, summon monster IX (fiends only), unhallow, unholy blight
Abilities Str 30, Dex 11, Con 34, Int 8, Wis 11, Cha 15
SQ Transparent
Feats Several
Skills These will be awesome. It has 182 points to spend.
Acid (Ex): The doom cube’s acid does not harm metal or stone.
Engulf (Ex): Although it moves slowly, the doom cube can simply mow down Huge or smaller creatures as a standard action. It cannot make a slam attack during a round in which it engulfs. The doom cube merely has to move over the opponents, affecting as many as it can cover. Opponents can make opportunity attacks against the cube, but if they do so they are not entitled to a saving throw. Those who do not attempt attacks of opportunity must succeed on a DC 32 Reflex save or be engulfed; on a success, they are pushed back or aside (opponent’s choice) as the cube moves forward. Engulfed creatures are subject to the cube’s paralysis and acid, and are considered to be grappled and trapped within its body. The save DC is Strength-based and includes a +1 racial bonus.
Paralysis (Ex): The doom cube secretes an anesthetizing slime. A target hit by the cube’s melee or engulf attack must succeed on a DC 33 Fortitude save or be paralyzed for 3d6 rounds. The cube can automatically engulf a paralyzed opponent. The save DC is Constitution-based.
Transparent (Ex): The doom cube is hard to see, even under ideal conditions, and it takes a DC 15 Spot check to notice one. Creatures who fail to notice the cube and walk into it are automatically engulfed.
...I think that does it, so far. Build advice, please. This is intended to be a mini-boss.
