Mhelgull’ixith
Here's one for ya...
MHELGULL’IXITH, Lesser Pseudonatural Gelatinous Corrupted Tyrannosaurus
Huge Outsider (Evil, Extraplanar)
Hit Dice: 18d10+108 (207 hp)
Initiative: +1
Speed: 20’
AC: 20 (-2 size, +1 dex, +11 natural)
Base Attack/Grapple: +18/+37
Attack: Bite +28 melee
Full Attack: Bite +28 melee, slam +22 melee
Damage: Bite 10d6+11 plus 9 vile plus 1d8 acid, slam 2d6+5 plus 9 vile plus 1d8 acid
Face/Reach: 15’/10’
Special Attacks: Improved grab, swallow whole, true strike 1/day
Special Qualities: Alternate form, blindsight 60’, DR 10/+3, darkvision 60’, fast healing 9, immunities (polymorphing, stunning), resilient, resistances (acid and electricity 20), scent, SR 25
Saves: Fort + 17 (+4 vs. poison, sleep and paralysis), Ref +11, Will +12 (+4 vs. mind-affecting effects, sleep and paralysis)
Abilities: Str 32, Dex 10, Con 23, Int 3, Wis 13, Cha 8
Skills: Climb +33, Hide -4, Listen +25, Spot +25, Swim +33
Feats: Alertness, Cleave, Improved Bull Rush, Large and In Charge, Power Attack, Run, Weapon Focus (bite)
Climate/Terrain: Any land or underground
Organization: Solitary or pair
Challenge Rating: 17
Treasure: None
Alignment: Always neutral evil
Advancement Range: 29-36 HD (Gargantuan), 37-54 HD (Colossal)
Description: Mhelgull’ixith is a hideous creature, its body about 50’ long and composed of stringy gelatinous material that resembles ectoplasm. It is truly disgusting, giving off a fetid odor, especially from its black mouth. Mhelgull’ixith weighs in at over seven tons in weight.
Combat: Mhelgull’ixith is a stupid creature that prefers to savage opponents with its mighty bite. Those it strikes are seldom able to fully recover due to the vile damage that it inflicts.
Improved Grab (Ex): On a successful bite, Mhelgull’ixith can make a free grapple check on a creature at least two sizes smaller than it. If it gets a hold, it can attempt to swallow its foe next round on another successful grapple check.
Swallow Whole (Ex): Mhelgull’ixith can swallow a grappled opponent of Medium or smaller size. If successful, the victim suffers 4d6+11 points of crushing damage and 11 points of acid damage each round. Cutting its way free requires the victim to have a light weapon in hand; it must deal 25 points of damage to the gizzard (AC 26).
True Strike (Su): 1/day, Mhelgull’ixith can make a single attack with a +20 insight bonus to the attack roll. This attack is not affected by the miss chance caused by concealment.
Alternate Form (Su): Mhelgull’ixith can take the form of a tentacled, writhing thing that offends the senses, giving all creatures a -1 morale penalty to attack rolls against it.
Resilient (Ex): Due to its gelatinous nature, Mhelgull’ixith cannot be flanked, suffers 1d6 less damage from sneak attacks, and suffers only half the extra damage inflicted by a critical hit.
The rest of the special abilities are pretty self-explanatory.