Source: Construct Handbook, pg(s). 44
Inubrix golems are a type of golem whose body incorporates inubrix, a skymetal that can pass through iron and readily accept magical enhancements from necromancy. Inubrix golems are animated by negative energy unlike other golems, and can walk on the air and expel a yellowish gas that deadens the sense of victims. Most golem builders craft inubrix golems with a skeletal aesthetic, which adds to their mystique. Inubrix golems are 11 feet tall, weigh 5,000 pounds, and constantly emit a low bass rumble.
Abysibrix golems are made from an alloy of inubrix and abyssium, a skymetal that glows blue-green and sickens creatures exposed to it. Abysibrix golems are sturdier than inubrix golems but cannot phase through iron.
Iunbrix golems are extremely rare on Golarion and can only be found where access to skymetals is easy. They were first crafted in Numeria by the Technic League to serve as scouts and shock troops, but turned out ill-suited for both tasks, as they can neither communicate with their creators nor harm robots made from iron. They do not make good bodyguards, being unable to block iron weapons, but can be hidden behind iron walls to ambush unsuspecting foes. Some Technic League officers employed inubrix golems to assassinate their rivals, but it took little time for survivors to line their lairs with materials other than iron.