This is my third attempt to post some feedback here; I've been timing out all afternoon. Note to self: Select All and press Control-C before posting. ;)

As usual, I haven't read the feedback from others. yeah, you know the routine by now...

Quote Originally Posted by Fax_Celestis View Post
Hit Dice: 30d10+150 (300 hp)
So, 30 HD and a +7 Con mod should be +210 hit points right? Not 150? And average hit points should be 375.

Armor Class: 30 (-4 size, +24 natural), touch 6, flat-footed 30
Colossal is a -8 to AC and attacks, not -4. You'll need to adjust accordingly.

Base Attack/Grapple: +16/+40
A 30 HD magical beast should have a BAB of +30 (assuming epic rules don't kick in, which seems to be the case looking at a few critters in the SRD).

Grapple should then be +63 (+30 BAB, +16 size mod, +17 Str)

Attack: Bite +30 melee (2d8+12)
Full Attack: Bite +30 melee (2d8+12) and crush (3d10+24)
The bite attack should be +40 (+30 BAB, +17 Str, -8 size, +1 Weapon Focus). The damage should be +17, not +12.

Does "crush" have an attack value? If not, it's just a special attack and not listed on the full attack line. Also, the bonus there seems to be double Strength, which would be +34.

I'm beginning to get the feeling you made significant changes to some stats at some point and missed some updates...

Special Attacks: Improved grab, swallow whole, crush
Alphabetical order.

And to post a pedantic nit pick, Improved grab needs to be associated with a particular attack mode. Obviously, it's "bite," which is why I classified it as a pedantic nit pick. ;)


Special Qualities: Tremorsense 240 ft., Blindsense 60 ft., Resistance (Cold, Acid, Electricity) 20, Damage Reduction 20/adamantine, Spell Resistance 30, Force Absorption, Force Sensitivity
Again, alphabetical order. Also, only the first entry on the line needs to be capitalized.

I might consider lowering the DR down to 15, just to give groups without an adamantine weapon a chance.

Your SR is going to be fairly tough to bypass (a 17th level caster would need to roll 13 or better - assuming no feats or such). Is that intended? If so, that's OK. Just making sure you have it where you want it.

Saves: Fort +17, Ref +10, Will +4
I get very different save values from what you have.

Fort and Ref are good for a magical beast. A good save is calculated as (Hit Dice / 2) + 2. So the base save for Fort and Ref = +17.

Will save is a "bad" save. That's calculated as HD / 3, or +10 in this case.

So we have base saves of +17/+17/+10. You have ability modifiers of +7/+0/-1, so the total saves should be +24/+17/+9.

Skills: Listen +20
You've spent 21 skill points. You have a total of 33 to spend.

Feats: Awesome Blow, Crush, Frightful Presence, Improved Bull Rush, Improved Initiative, Mighty Rage (3/day), Power Attack, Spring Attack, Weapon Focus (bite)
A few things here.

Crush and Frightful Presence aren't feats.

Might Rage is an epic feat for which you do not meet the prereqs.

You also do not meet the prereqs for Spring Attack.

You should have a total of 11 feats, not counting any bonus feats you want to dish out (like Mighty Rage ;) ). Even if I count the things that aren't feats, you only have 9 listed here.

Environment: Auleauk Desert (Island of Naudia Diva, subplane of the Beastlands)
Is the Beastlands WotC IP? The planes are sort of funny with what is and isn't WotC IP. For example, "Ysgard" is not WotC IP; however, if you call it "Heroic Domains of Ysgard" you've now travelled into WotC's IP.

Going deeper, is the Auleauk Desert WotC IP?

Advancement: 30-40 HD (Colossal); 40-50 HD (Colossal+)
Your advancement should start at 31 HD, not 30. You've already detailed how a 30 HD critter should look.

You hear a rumbling sound and see a crease form in the sand in front of you, traveling towards you at an alarming rate. Diving out of its way, you see the earth behind you erupt upwards and a terrible brown-gray wormlike creature roars...
You're assuming stuff on the parts of the PCs. It's something that's really hard to avoid, but it makes a big difference in this flavor text. Try something like:

Quote Originally Posted by Suggested Flavor Text
The ground itself rumbles moments before it cracks open; a terrible brown-grey wormlike creature errupts from the fissure, it's mouth full of pointed teeth easily as long as an ogre's arm.
Continue describing your creature from there. Does the skin have a certain texture or moisture that's observable? Any other features worth noting here?

Forcehunter Sandworms (called "toveaxdirupetarak" in Horjinic) are vicious warriors of the desert, known for their rage and strength. They have no eyes, but they do have a keen sense of smell and an even keener sense of touch. They are gigantic monstrocities, feared for their ability to eat opponents whole.
Don't capitalize the creature name.

Swallow Whole (Ex)
A forcehunter sandworm can try to swallow a grabbed opponent of a smaller size than itself by making a successful grapple check. Once inside, the opponent takes 3d8+18 points of crushing damage plus 16 points of acid damage per round from the sandworm’s gizzard. A swallowed creature can cut its way out by using a light slashing or piercing weapon to deal 50 points of damage to the gizzard (AC 20). Once the creature exits, muscular action closes the hole; another swallowed opponent must cut its own way out. A Gargantuan sandworm’s interior can hold 2 Large, 8 Medium, 32 Small, 128 Tiny, or 512 Diminutive or smaller opponents.
The "+18" to damage appears to be 1.5 the amount of Strength you were using; so this value appears to be wrong here, and should be +25.

Is the acid damage a fixed value, or is it computed somehow? If it's computed, you need to tell GMs how.

Mighty Rage (Ex)
A forcehunter sandworm will immediately enter a rage if it fails to swallow an opponent. In a rage, a forcehunter sandworm temporarily gains a +8 bonus to Strength, a +8 bonus to Constitution, and a +4 morale bonus on Will saves, but takes a -2 penalty to Armor Class. The increase in Constitution increases the sandworm’s hit points by 4 points per Hit Die, but these hit points go away at the end of the rage when its Constitution score drops back to normal.
This strikes me more as an ability rather than a feat. I'd stick it up in the SA line and remove it from the feat line; then you don't have to worry about it not meeting the pre-reqs for the Epic feat.

Crush (Ex)
This special attack allows a forcehunter sandworm to land on opponents as a standard action, using its whole body to crush them. Crush attacks are effective only against opponents three or more size categories smaller than the sandworm (though it can attempt normal overrun or grapple attacks against larger opponents).

A crush attack affects as many creatures as can fit under the sandworm's body. Creatures in the affected area must succeed on a Reflex save (DC equal to that of the sandworm's hit dice plus it's strength modifier) or be pinned, automatically taking bludgeoning damage during the next round unless the sandworm moves off them. If the sandworm chooses to maintain the pin, treat it as a normal grapple attack. Pinned opponents take damage from the crush each round if they don’t escape.

A crush attack deals the indicated damage plus 1-1/2 times the sandworm’s Strength bonus (round down).
OK, so if it's a standard action to attempt a crush attack, it can't be used in a full attack (see above).

Strength (underlined above) should be capitalized.

Force Sensitivity (Ex)
Whenever any force effect (such as a wall of force, mage armor, or magic missile spell) is used within 10 miles of a forcehunter sandworm, it becomes immediately aware of the source and is filled with a desire to destroy it. It beelines for the source of the force effect at double its full burrowing speed, to the exclusion of all other creatures, and will attack it immediately upon arrival.
Why? That's a question you should answer in the monster's flavor text.

Force Absorption (Ex)
>>Snippy McSnip Was Here!!<<

A force spell that deals damage (like a magic missile) does not heal a forcehunter sandworm as normal; instead of healing twice the caster level of the spell, it instead heals an amount equal to damage it would have been dealt.

>>And here, too!<<
OK, a few things.

In the paragraph I left behind, you talk about force spells "healing" the sandworm. But in your first paragraph, you didn't actually say it healed existing damage. I had to actually read it twice to understand. Of course, I'm senile and it's Monday - not a good combination.

Second: Is this true against any force effect? Even those generated by epic level spells? Or by deities?

Third: This strikes me more as a Supernatural ability rather than Extraordinary, mostly because of the whole dispelling thing.

***

Overall, not bad (math errors aside ;) ). It has two big vulnerabilities.

1) Ranged Weapons.
2) Will save spells. Illusions, in particular, strike me as the way to handle this thing.

Just some things to keep in mind.