My "New World" Campaign (Desert Thing)

Desert Thing (From Deadlands D20)
Large Aberration
Hit Dice: 8d8+24 (56)
Initiative: +3
Speed: Immobile (10ft. per hour)
Armor Class: 12 (-1 size, +0 Dex (immobile), +3 natrual), touch 9, flat-footed 12
Base Attack/Grapple: +6/+12
Attack: Tentacle rake +8 melee (1d6+2)
Full Attack: 8 tentacle rakes +8 melee (1d6+2) and 1 bite +6 melee (2d6+1)
Space/Reach: 10ft./20ft.
Special Attacks: Improved grab
Special Qualities: Concealment, damage resistance, tremorsense
Saves: Fort +5, Ref +5, Will +8
Abilities: Str 15, Dex 16, Con 17, Int 6, Wis 14, Cha 9
Skills: Hide +13, Listen +13
Feats: Improved Grapple, Multiattack, Weapon Finesse (tentacles)
Environment: Any desert
Organization: Solitary
Challenge Rating: 4
Treasure: None
Alignment: Neutral evil
Advancement: 9-12 HD (Large), 13-15 (Huge)
Level Adjustment:-
What desert would be complete without a tentacle beastie lurking beneath the sands? Desert things move very slowly beneath the dunes, setting up shop along popular trails or in or near a water hole. When a hapless traveler passes by, the thing grabs it legs or hooves with its long tentacles and drags it into its circular maw.
Combat
Tremorsense (Ex): Desert things can sense approaching prey up to 150 feet distant on an opposed Move Silently verse its Listen roll. The creature attacks when its prey gets within reach of its tentacles.
Tentacles (Ex): Each of the desert thing’s eight tentacles can attempt to pull prey closer to its gaping maw. First a tentacle has to hit the characters. If it does, it entangles the victim as well as causing damage, then start to reel in its prey. This is an opposed Strength roll. For every point by which the creature wins, it drags its prey 5 ft. closer to its gnashing teeth. A character who beats the desert thing in an opposed Strength roll on subsequent turns breaks free, requiring it to hit again.
The only other way to escape the creature is to kill the mouth or mangles its tentacles. Each tentacle has 10 hit points (in addition to the body’s hit points) and is AC 17 (+2 size, +3 Dex, +2 natural)
Damage Resistance (Ex): The beast lies protected under several inches of sand, giving the body 100% concealment. Against firearms and slashing attacks, the sand also provides it with 4 points of damage reduction. Piercing weapons do a single point of damage to the thing’s blubbery body or tentacles.
Skills: Desert things receive a +7 racial bonus to Hide and Listen rolls.