Scylla

This horrifying creature has the upper body of a beautiful woman, but a lower body of snapping wolf heads and writhing tentacles.
 

Scylla (CR 16)

Huge Aberration (Aquatic)
Alignment: Chaotic Evil
Initiative: +11
Senses: All-Around Vision, Blindsight 30 feet, Darkvision 60 feet, Low-Light Vision, See Invisibility; Perception +29
Aura: frightful presence (30 feet, DC 26),
  Speed: 30 feet, Swim 50 feet
Space: 15 feet
 

Defense

Armor Class: 30, touch 20, flat-footed 18 (+11 Dex, +1 dodge, +10 natural, -2 size)
Hit Points: 250 (20d8+160) Fast Healing 10
Saving Throws: Fort +14, Ref +17, Will +18
Freedom of Movement, improved Evasion
Damage Reduction: 10/cold iron and lawful
Immunity: cold, charm effects, confusion and insanity effects
Energy Resistance: acid 20, fire 20
Spell Resistance: 27
 

Offense

Melee: 4 bites +25 (1d8+8/19-20 plus bleed), 4 tentacles +23 (1d6+4 plus Grab)
Reach: 15 feet
  Special Attacks: Bleed (1d6), Constrict (1d6+8)
  Spell-Like Abilities (CL 16th; Concentration +22):

Statistics

StrDexConIntWisCha
27 (+8) 32 (+11) 27 (+8) 20 (+5) 23 (+6) 22 (+6)
Base Attack Bonus: +15
CMB +25 (+29 Grapple)
CMD 47 (can't be tripped)
  Feats: Combat Reflexes, Dodge, Improved Critical (bite), Multiattack, Vital Strike, Weapon Finesse, Weapon Focus (bite), Weapon Focus (tentacles)
  Skills: Acrobatics +34, Bluff +26, Intimidate +29, Knowledge (nature) +25, Perception +29, Sense Motive +26, Stealth +26, Swim +39, Use Magic Device +26
  Languages: Abyssal, Aquan, Common
  Special Qualities: Amphibious, Change Shape (1 humanoid form, alter self ), undersized weapons

 

Special Abilities

NONE
 

Ecology

Environment: Any Aquatic
Organization: solitary
Treasure: triple

  The scylla is one of the more nightmarish aberrations to blight the mortal world. Conflicting tales of her origins abound, from demonic flesh-crafting and arcane experiments to a divine curse handed down by a vengeful deity. The most popular stories cast the first scylla as the monstrous spawn of a union between a mortal and a god.
  Whatever the case, scyllas are fortunately quite rare, enough so that many consider them nothing more than tall tales told by sailors deep in their cups. Scyllas dwell along major shipping lanes, often near coastlines, where they use their spell-like abilities to lure entire ships to their doom. The hideous monsters are intelligent creatures, though half-mad with hunger and self-loathing.
  They normally do not use weapons, but when they do, they prefer to fight with light weapons wielded by their human-sized upper arms. However, they much prefer to keep their hands free to utilize magic items like wands, staves, and other powerful devices.