The goal being to facilitate items such as a djinn's lamp, this sort of thing.
I've put together an example raw posted in the spoiler section below: In this example, we define the secret thats generated during world gen, and specify which item is created in place of a slab, which in this case, is a large gem. Lastly, we attach specific interactions to the secret object, which allows creatures who are in possession of the object to use those interactions, as long as they retain possession of the object.
The example we use is a gemstone that transforms its owner into a demon and back after some time. Although, the creature will stop aging after having used the item at least once.
[OBJECT:INTERACTION]
[INTERACTION:DEMONIC_HOLY_STONE]
[I_SOURCE:SECRET]
[IS_NAME:holy stone]
[IS_SPHERE:WEALTH]
[IS_SECRET_GOAL:IMMORTALITY]
[IS_SECRET:SUPERNATURAL_LEARNING_POSSIBLE]
[IS_SECRET:ITEM_POSESSION_RESTRICTED:STANDARD_ITEM_TOKEN:GEM:NONE]
[ITEM_POSSESSION_RESTRICTED_INTERACTION]
[CAN_DO_INTERACTION:MERGE_SPIRIT_WITH_FLESH_OF_THE_DEVIL]
[CDI:TARGET:A:SELF_ONLY]
[CDI:I_LOCATION:CONTEXT_CREATURE]
[CDI:ADV_NAME:Forge pact with devil]
[CDI:USAGE_HINT:DEFEND]
[CDI:USAGE_HINT:ATTACK]
[CDI:VERB:seals contract with devil:seals contract with devil:NA]
[CDI:WAIT_PERIOD:5000]
[INTERACTION:MERGE_SPIRIT_WITH_FLESH_OF_THE_DEVIL]
[I_SOURCE:CREATURE_ACTION]
[I_TARGET:A:CREATURE]
[IT_LOCATION:CONTEXT_CREATURE]
[I_EFFECT:ADD_SYNDROME]
[IE_TARGET:A]
[IE_IMMEDIATE]
[SYNDROME]
[SYN_CONCENTRATION_ADDED:1000:0]
[CE_BODY_TRANSFORMATION:START:0:END:2500:ABRUPT:DWF_STRETCH:144]
[CE:CREATURE_CASTE_FLAG:DEMON]
[CE_ADD_TAG:NO_AGING:START:0:ABRUPT:DWF_STRETCH:144]
Coming into contact with the secret object might also permit the normal transference of secrets, syndromes, interactions, etc. However in the above example we decline to make any permanent changes to creatures who come into contact with the object, in order to narrow the example's focus.