Artifact suit of armor (type is unspecified, perhaps a ring mail or chain mail) that is unaligned and operates like magic armor in the Legend of Zelda. When worn, it drains your gold at a constant rate, and when you take damage, you lose a somewhat randomized amount of gold, in exchange for partially or completely negating the damage. Gold is consumed at some rate higher than 1 per turn, and it is lost for damage at some rate higher than 1 per hit point.

If you have no gold while wearing it, you become either very slow or very encumbered.

Croesus may occasionally generate wearing this armor, along with some gold to supply it. Otherwise it generates like any unaligned artifact.

Variants that give Croesus armor made of gold should also have a small chance that his body armor is replaced with gold dragon scale mail.

Croesus may generate disguised as another @, possibly hidden among his soldiers.

Croesus generates wearing a random gold amulet (probably not change or strangulation, though).

If you tell a vault guard that your name is Croesus, and you are wearing gold armor, they might lead you out of the vault without forcing you to drop any gold. The chance of this outcome increases for each piece of gold armor you are wearing.

Level flag that prevents mapping as long as the local “boss” is alive (nemesis if anywhere in the Quest, demon lords/Croesus on their own levels). Maybe make the ‘nommap’ field 2 bits instead of 1.

Croesus is able to displace other monsters, because he’s the king. Perhaps all king-type monsters should be able to displace other monsters.

Give Croesus a gold-stealing attack in addition to the regular attacks he has now.

Croesus is generated with 2 random amulets and 5 random rings (bling) in inventory.

Carrying gold items openly causes leprechauns, dragons, and Croesus to be automatically aggravated.