Bone Lurker (CR 2)

Large Undead
Alignment: Always neutral
Initiative: +4

AC: 12 (-1 size, +0 Dex, +3 natural), touch 9, flat-footed 12
Hit Dice: 3d12 (19 hp)
Fort +1, Ref +1, Will +3
Speed: 20 ft., fly 30 ft. (poor)
Space: 5 ft. by 10 ft./5 ft.
Base Attack + ; Grapple +
Attack: slam +5 melee
Damage: Slam 1d8+7
Special Attacks/Actions: Constrict 1d8+7, improved grab, paralysis
Abilities: Str 20, Dex 10, Con -, Int -, Wis 10, Cha 11
Special Qualities: Immunities, undead traits
Feats: Improved Initiative
Skills: -
Advancement: 4 HD (Large); 5-9 HD (Huge)
Climate/Terrain: Any land and underground
Organization: Any
Treasure: None

Source: Web

Bone monsters are undead creatures assembled from the bones of fallen creatures and knitted together with necromantic magic. They are mindless automatons that obey the orders of their evil masters. If destroyed, they collapse into piles of unconnected bones.

These undead creatures appear as portcullises or gridwork-curtains created from interlaced human and beast bones adorned with sharp bone spurs.

A bone lurker can be created by means of an animate dead spell, and it requires three corpses to create one bone lurker.