All pieces of equipment have a unique identifier, also called an UUID. UUID's can be used to reference the exact piece of equipment that you want to wear, remove, get out of a container or storage, or cast spells on, among other things. Uuids on any piece of equipment can be learned using the insult command if you know any other keyword for the equipment. FOr example, to get the uuid for a silver anklet of quickening, you would get the anklet into your inventory, then type
insult anklet You will receive an input somewhat like this: You insult silver anklet quickening 07edff7a8d21add714d5abc6a9dc1cab.
The uuid for the anklet is "07edff7a8d21add714d5abc6a9dc1cab". If I wanted to get the anklet out of the continer, I could use
get anklet bag
or I could use get 07edff7a8d21add714d5abc6a9dc1cab bag
I could also use just the first three letters of the uuid. Uuids are unique enough that the first three letters almost always suffice to reference the correct piece.
A builder uses uuid's to reference mobs in his or her area. Each uuid is treated as a different kind of mob by the mud, even if the mobs on each uuid are exactly the same. However, the global exp thwacker keeps an eye on how many times each kind of mob is killed, and penalizes players if they kill too many of the same type of mob. Therefore, many builders place just a few mobs on each uuid so that the xp will stay high. Older areas suffer from the fact that all their mobs are on the same uuid, causing them to be thwacked quickly.
Note: unlike object UUID's, players cannot see the UUID's for mobs.