Gravorg (CR 8)
Large Magical Beast
Alignment: Always neutral
Initiative: +3 (-1 Dex, +4 Improved Initiative); Senses: darkvision 60 ft., low-light vision, Listen +5, and Spot +5
AC: 13 (-1 size, -1 Dex, +5 natural), touch 8, flat-footed 13
Hit Dice: 10d10+30 (85 hp); DR: 5/magic
Fort +10, Ref +6, Will +4
Speed: 20 ft., climb 20 ft.
Space: 10 ft./5 ft.
Base Attack +10; Grapple +18
Attack: Claw +13 melee
Full Attack: 2 claws +13 melee and bite +8 melee
Damage: Claw 1d6+4, bite 1d8+2
Special Attacks/Actions: Reverse gravity
Abilities: Str 19, Dex 8, Con 17, Int 2, Wis 13, Cha 8
Special Qualities: SR 19
Feats: Ability Focus (reverse gravity); Alertness; Improved Initiative; Power Attack
Skills: Climb +16, Hide +0*, Listen +5, and Spot +5
Advancement: 11-15 HD (Large); 16-20 HD (Huge); 21-25 HD (Gargantuan); 26-30 HD (Colossal)
Climate/Terrain: Any underground
Monster Manual II
A gravorg uses reverse gravity to bounce its prey off ceilings or other overhangs, then dismisses the effect to drop the opponents back to the floor. Only when its victims appear unconscious or dead does a gravorg come out of hiding and begin to feed.
A gravorg caught outdoors uses its reverse gravity ability to throw predators in the air repeatedly until the latter either flee or become disabled. The monster uses its claws and teeth almost entirely for tearing open its prey rather than for self-defense.
Reverse Gravity (Sp): At will - a gravorg can produce an effect like that of a reverse gravity spell (caster level 10th; Reflex save DC 18), except that the range is 200 feet and it affects an area of up to five 10-foot cubes. The monster simply stacks the cubes to reach a ceiling or other overhang, then uses any remaining area to disrupt the prey's companions.
Skills: A gravorg receives a +10 bonus on Hide checks in subterranean areas.