Foo dog

Foo Dog
Encounter
Climate/Terrain	Astral Plane, Ethereal Plane, Arborea, Ysgard (occasionally elsewhere)
Activity Cycle	Any
Frequency	Rare (7%)
Organization	Mated pair (2)
Lair	The realms of Chaotic Good gods
Surprise	Foo dogs can become invisible and ethereal at will, and can travel astrally and ethereally whenever they choose to.
Interaction
Intelligence	Very (11-12)
Morale	Elite (13)
Alignment	Chaotic Good
Languages	Foo Dog, Foo Creature, the languages of any humanoids they are in contact with
Combat
Size	Medium (3-4' long)
Hit Dice	7+7
Armor Class	0 (+10)
Movement	27 (270 ft./round)
Defenses	45% magic resistance Evil creatures take a -1 penalty to attack and damage rolls against foo dogs
Enhancements	Foo dogs have a +1 bonus to attack and damage rolls when targeting Lawful Evil creatures. When in combat with any evil creatures, the foo dog has a further +2 bonus to attack rolls. Additionally, a foo dog who barks for 7 rounds has a 20% chance to gate in 1d6 additional foo dogs.
Actions	Claw/Claw/Bite
	THAC0 13 (+7)	1d4+1/1d4+1/1d12 damage
Rewards
Treasure	Nil
Level/XP	IX/6,000 xp

Foo dogs are celestial creatures that serve the gods of Chaos and Good, along with those mortals that impress them.

Foo dogs have short, bush-tipped tails, long, floppy ears, and broad noses. Their fur is typically golden or black, but also may be white, green, violet, or gray. They have large, blunt heads with wide-set, bulging eyes. Their bodies are somewhat leonine, with thick fur and padded feet. Their forelegs are lion-like claws, while their hind legs are more canine.

Foo dogs have been known to help mortals on the material plane, especially if the person they are helping is kind and benevolent, or if the cause appeals to the foo dog's sense of justice. However, a stay of more than a few weeks outside of their home realm is rare.

Foo dogs are said to be the spirits of petitioners who serve Chaotic Good deities, who have been given this form, and proxy status, as a reward for exceptional service.

It is believed that a foo dog only ages when they cease to perform good works, so younger foo dogs often regard their elders as inferiors. Very ancient foo dogs often move into isolated corners of the less-traveled planes to escape this derision.

Foo dogs can eat any inorganic matter, and are especially fond of gems and precious metals. Platinum and silver are especially delicious to them. Foo dogs who accompany adventurers often ask for a portion of the treasure to eat.

Foo dogs are closely related to foo lions - the lions are a more powerful type of foo creature.

Sources

Monster Manual II (1e)

Kara-Tur Monstrous Compendium (2e)

Planescape Monstrous Compendium I (2e)