Sheet Ghoul (CR 2)

Medium Undead
Alignment: Chaotic evil
Initiative: +2 (Dex); Senses: darkvision 60 ft., Listen +10, and Spot +8

AC: 16 (+2 Dex, +4 natural), touch 12, flat-footed 14
Hit Dice: 4d12 (26 hp)
Fort +0, Ref +2, Will +0
Speed: 30 ft.
Space: 5 ft./5 ft.
Base Attack +2; Grapple -3
Attack: 2 claws +3 melee, bite +0 melee
Full Attack: 2 claws +3 melee, bite +0 melee
Damage: Claws 1d3+2, bite 1d6+2
Special Attacks/Actions: Acid spray
Abilities: Str 14, Dex 15, Con -, Int 10, Wis 14, Cha 14
Special Qualities: Undead
Feats: Multiattack; Weapon Finesse (claw)
Skills: Climb +6, Hide +4, Jump +6, Listen +10, Move Silently +8, Search +6, and Spot +8
Advancement: 5-8 HD (Medium-size); 9-12 HD (Large)
Climate/Terrain: Any land or underground
Organization: Solitary (1)
Treasure: None

Source: Dragon #287

A sheet phantom can merge with the body of any humanoid it slays. The process takes about 12 hours, after which time the victim and sheet phantom transform into a sheet ghoul.

A sheet ghoul is the result of a sheet phantom merging with its humanoid victim. It looks like a normal ghoul, but closer inspection might reveal wispy strands of white material clinging to its face like cobwebs or a decaying shroud. This is the remains of the sheet phantom's linen form.

Sheet ghouls devour carrion and freshly killed prey.