Ghast (CR 3)

Medium Undead
Alignment: Always chaotic evil
Initiative: +3 (Dex); Senses: darkvision 60 ft. and Spot +8
Languages: usually Common

AC: 17 (+3 Dex, +4 natural), touch 12, flat-footed 14
Hit Dice: 4d12+3 (29 hp)
Fort +1, Ref +4, Will +6
Speed: 30 ft.
Space: 5 ft./5 ft.
Base Attack +2; Grapple +5
Attack: Bite +5 melee
Full Attack: Bite +5 melee and 2 claws +3 melee
Damage: Bite 1d8+1 and paralysis; claw 1d4+1 and paralysis
Special Attacks/Actions: Stench, paralysis, ghoul fever
Abilities: Str 17, Dex 17, Con -, Int 13, Wis 14, Cha 16
Special Qualities: Undead, +2 turn resistance
Feats: Multiattack; Toughness
Skills: Balance +7, Climb +9, Hide +8, Jump +9, Move Silently +8, Search +8, and Spot +8
Advancement: 5-6 HD (Medium-size)
Climate/Terrain: Any land and underground
Organization: Solitary, gang (2-4), or pack (2-4 plus 7-12 ghouls)
Treasure: Standard

Source: Monster Manual

Although these creatures look just like their lesser kin, ghouls, they are far more deadly and cunning.

That ghasts were once people is obvious to those with the courage to look upon them. Although they still appear more or less humanoid, their mottled, decaying flesh is drawn tight across clearly visible bones. The transformation from living beings into fell things of the night has warped their minds, making them cunning and feral. Their eyes burn like hot coals in their sunken sockets.

Ghasts speak the languages they spoke in life (usually Common).