Annihilator (CR 15)

Medium Aberration
Alignment: Always neutral evil
Initiative: +9 (+5 Dex, Improved Initiative); Senses: darkvision 60 ft., scent, Listen +14, and Spot +15

AC: 25 (+5 Dex, +10 natural), touch 15, flat-footed 20
Hit Dice: 20d8+20 (110 hp); DR: 15/magic
Fort +7, Ref +11, Will +13
Speed: 40 ft.
Space: 5 ft./5 ft.
Base Attack +15; Grapple +15
Attack: Antennae touch +21 melee (disintegration)
Full Attack: 2 antennae touches +21 melee (disintegration)
Damage: -
Special Attacks/Actions: Disintegration
Abilities: Str 10, Dex 21, Con 13, Int 2, Wis 13, Cha 12
Special Qualities: SR 31
Feats: Alertness; Blind-fight; Combat Reflexes; Improved Initiative; Track; Weapon Finesse; Weapon Focus (antennae)
Skills: Listen +14 and Spot +15
Advancement: 21-40 HD (Large); 41-60 HD (Huge)
Climate/Terrain: Underground (Lower Underdark)
Organization: Solitary
Treasure/Possessions: None

Source: Underdark

Disintegration (Su): A successful touch attack by an annihilator's antennae causes its target to disintegrate, as though subjected to the disintegrate spell. Any creature or magic item so touched that makes a DC 21 Fortitude save takes 5d6 points of damage instead of disintegrating. The save DC is Constitution-based.