Rokuro-Kubi (CR 2)

Medium Monstrous Humanoid
Alignment: Usually chaotic evil
Initiative: +6 (+2 Dex, +4 Improved Initiative)

AC: 12 (+2 Dex), touch 12, flat-footed 10
Hit Dice: 4d8 (18 hp)
Fort +1, Ref +6, Will +6
Speed: 30 ft.
Space: 5 ft./5 ft. (20 ft. with bite)
Base Attack +4; Grapple -1
Attack: Katana +7 melee, bite +1 melee
Full Attack: Katana +7 melee, bite +1 melee
Damage: Katana 1d10+3, bite 1d4+1
Special Attacks/Actions: Improved grab, constrict 1d6+2
Abilities: Str 14, Dex 15, Con 10, Int 11, Wis 14, Cha 10
Special Qualities: -
Feats: Improved Initiative; Skill Focus (disguise)
Skills: Bluff +7, Diplomacy +2, Disguise +10, and Intimidate +2
Advancement: By character class
Climate/Terrain: Any land
Organization: Solitary or party (2-5)
Treasure/Possessions: Standard

Source: Oriental Adventures

Improved Grab (Ex): To use this ability, the rokuro-kubi must hit with its bite attack. If it gets a hold, it can constrict with its snakelike neck.

Constrict (Ex): A rokuro-kubi deals 1d6+2 points of damage with a successful grapple check against Medium-size or smaller creatures. While constricting the rokuro-kubi can use its weapon to attack only the constricted opponent.

Kokuro-kubi are sly and cunning, and delight in causing suffering. They sometimes befriend a group of travelers or a peasant family, only to slay them one at a time in secret. They commonly disguise themselves as travelers and attack other travelers they meet on the road.