Experiment ZQ-29 is an invisible spider silk golem that carries some excellent treasure. It is impossible to see the spider silk golem- ESP does not work because golems have no minds; and Infravision doesn't work because golems are not living creatures that give off body heat.
If you have a stethoscope you can learn that "something" has the following stats...
|Random Stats||-||Permanent States|
|Size||250||Haste, Infravision, Invisible, TeleControl, Gas Immunity|
Whilst not one of the strongest golems in the game [spider silk is about as strong as arcanite], it has excellent dexterity meaning it often strikes limbs and can easily decapitate you if you can't defeat it or escape from it quickly enough. It is also incredibly fast.
If you defeat the golem you will get its spider silk armour (AV 18 +/- enchantment) a book of Sophos, a wand of cloning, scroll of change material, wand of teleportation, and wand of invisibility. The book of Sophos indicates that it has been created by either Sophos or his followers.
Note: Unlike other uniquies (or much like other golems), it does not wear or wield its equipment.