Displacer Beast (CR 4)

Large Magical Beast
Alignment: Usually lawful evil
Initiative: +2 (Dex); Senses: darkvision 60 ft., low-light vision, Listen +5, and Spot +5

AC: 16 (-1 size, +2 Dex, +5 natural), touch 11, flat-footed 14
Hit Dice: 6d10+18 (51 hp)
Fort +8, Ref +7, Will +3
Speed: 40 ft.
Space: 10 ft./5 ft. (10 ft. with tentacles)
Base Attack +6; Grapple +14
Attack: Tentacle +9 melee
Full Attack: 2 tentacles +9 melee and bite +4 melee
Damage: Tentacle 1d6+4, bite 1d8 +2
Special Attacks/Actions: -
Abilities: Str 18, Dex 15, Con 16, Int 5, Wis 12, Cha 8
Special Qualities: displacement, resistance to ranged attacks
Feats: Alertness; Dodge; Stealthy
Skills: Hide +10, Listen +5, Move Silently +7, and Spot +5
Advancement: 7-9 HD (Large); 10-18 HD (Huge)
Climate/Terrain: Temperate hills
Organization: Solitary, pair, or pride (6-10)
Treasure/Possessions: 1/10 coins, 50% goods, 50% items

Source: Monster Manual

Displacement (Su): A light-bending glamer continually surrounds a displacer beast, making it difficult to surmise the creature's true location. Any melee or ranged attack directed at it has a 50% miss chance unless the attacker can locate the beast by some means other than sight. A true seeing effect allows the user to see the beast's position, but see invisibility has no effect.

Resistance to Ranged Attacks (Su): A displacer beast gains a +2 resistance bonus to saves against any ranged spell or ranged magical attack that specifically targets it (except for ranged touch attacks).

Skills: A displacer beast receives a +8 racial bonus to Hide checks, thanks to its displacement power.

Displacer beasts rake opponents with their tentacles and bite foes that get close.