Nethersight Mastiff (CR 8)

Large Magical Beast
Alignment: Usually neutral
Initiative: +5 (+1 Dex, +4 Improved Initiative); Senses: darkvision 60 ft., low-light vision, scent, true sight, Listen +7, and Spot +6

AC: 15 (-1 size, +1 Dex, +5 natural), touch 10, flat-footed 14
Hit Dice: 10d10+30 (85 hp)
Fort +10, Ref +8, Will +6
Speed: 50 ft.
Space: 10 ft./5 ft.
Base Attack +10; Grapple +9
Attack: Bite +13 melee
Full Attack: Bite +13 melee
Damage: Bite 2d6+6
Special Attacks/Actions: Improved grab, wrenching attack
Abilities: Str 19, Dex 13, Con 17, Int 6, Wis 12, Cha 12
Special Qualities: ethereal bite
Feats: Alertness; Improved Initiative; Iron Will; Track
Skills: Jump +15, Listen +7, Spot +6, and Survival +4
Advancement: 11-15 HD (Large); 16-30 HD (Huge)
Climate/Terrain: Any cold or temperate land
Organization: Solitary or pack (5-20)
Treasure/Possessions: None

Source: Monster Manual II

Improved Grab (Ex): If a nethersight mastiff hits an opponent that is at least one size category smaller than itself with a bite attack, it (grapple bonus +18). If it gets a hold on an ethereal creature it can attempt a wrenching attack on the next round. Alternatively, the nethersight mastiff has the option to conduct the grapple normally, or simply use its jaws to hold the opponent (-20 penalty on grapple check, but the nether sight mastiff is not considered grappled). In either case each successful grapple check it makes during successive rounds automatically deals bite damage.

Wrenching Attack (Su): A nethersight mastiff can wrench a grabbed ethereal opponent onto the Material Plane by making a successful grapple check (grapple bonus +18). A wrenched opponent is then trapped on the Material Plane unless it has the means to return to the Ethereal Plane.

Ethereal Bite (Su): A nethersight mastiff's teeth have abilities similar to those of a ghost touch weapon, allowing it to bite ethereal creatures and negating the usual miss chance on any attack against an incorporeal creature.

Scent (Ex): A nethersight mastiff can detect approaching enemies, sniff out hidden foes, and track by sense of smell.

True Seeing (Su): This ability functions like the true seeing spell (caster level 16th), except that it is continuously active.

Skills: A nethersight mastiff receives a +5 racial bonus on Spot checks when hunting creatures that are on the Ethereal Plane.

Nethersight mastiffs are bold, aggressive carnivores that usually hunt in large packs, surrounding their prey to prevent escape, and then closing in for the kill. Because ethereal prey is more difficult to catch than Material Plane creatures, mastiffs always attack quickly and hold on with their jaws.