Phasm (CR 7)

Medium Aberration (Shapechanger)
Alignment: Usually chaotic neutral
Initiative: +6 (+2 Dex, +4 Improved Initiative); Senses: scent, tremorsense 60 ft., Listen +12, and Spot +12
Languages: telepathy 100 ft.,

AC: 17 (+2 Dex, +5 natural), touch 12, flat-footed 15
Hit Dice: 15d8+30 (97 hp)
Fort +11, Ref +11, Will +11
Speed: 30 ft.
Space: 5 ft./5 ft.
Base Attack +11; Grapple +12
Attack: Slam +12 melee
Full Attack: 2 slams +12 melee
Damage: Slam 1d3+1
Special Attacks/Actions: -
Abilities: Str 12, Dex 15, Con 15, Int 16, Wis 15, Cha 14
Special Qualities: Amorphous, alternate form, resilient
Feats: Alertness; Blind-fight; Combat Reflexes; Dodge; Improved Initiative; Mobility
Skills: Bluff +20, Climb +7, Craft (any one) +12, Diplomacy +12, Disguise +20 (+22 acting), Knowledge (any one) +18, Listen +12, Spot +12, and Survival +8
Advancement: 15-21 HD (Huge); 22-45 HD (Gargantuan)
Climate/Terrain: Any underground
Organization: Solitary
Treasure/Possessions: Standard

Source: Monster Manual

Amorphous (Ex): A phasm in its natural form is immune to poison, sleep, paralysis, stun, and polymorph. It is not subject to critical hits and, having no clear front or back, cannot be flanked.

Alternate Form (Su): Phasms can assume the form of any corporeal creature or object from Diminutive to Large size as a standard action.

Telepathy (Su): Phasms can communicate telepathically with any creature within 100 feet that has a language.

Tremorsense (Ex): A phasm can automatically sense the location of anything within 60 feet that is in contact with the ground, so long as it is touching the ground itself.

Skills: When using alternate form, a phasm receives a +10 circumstance bonus to Disguise checks.

When faced with potential danger, a phasm is equally likely to retreat, parley, or attack, as its fancy strikes. Phasms value new experiences: fresh scents and tastes, obscure facts, gossip, odd bric-a-brac, and the like. Those who offer a phasm such things stand a good chance of avoiding a fight.

If pursued or harassed, a phasm transforms into the most fearsome creature it knows, such as an adult white dragon or a fire giant, and attacks.

When seriously hurt, it changes to some fast or agile form and tries to escape.

Shapechanger Subtype

A shapechanger has the supernatural ability to assume one or more alternate forms. Many magical effects allow some kind of shape shifting, and not every creature that can change shapes has the shapechanger subtype.

Traits: A shapechanger possesses the following traits (unless otherwise noted in a creature's entry).