I owe this for my recent uncharitable thoughts. (Just the recent ones, mind you.)
A small, irregularly shaped ring made of what appears to be purplish chitin. It does not radiate magic. If worn, the character feels a brief stinging sensation, after which he can detect magic at will. In addition, he gains infravision as a dwarf, and if he already possesses infravision, the range is doubled.
If removed, the ring will crumble to dust. If left on, it crumbles after 1d3 days, although the wearer will find that his powers remain.
After 3d4 days, the wearer can comprehend languages.
After another 2d4 days, the character has ESP, which functions up to three times per day. At this point, strange dreams of bizarre planes and distant planets begin to trouble him.
After another 1d4 days, the character gains 1d4 points of Intelligence. One axis of his alignment changes randomly, at the DM's discretion. The character becomes ill-tempered and has frequent headaches.
Finally, after a final 1d3 days, the character dies as a purple, centipede-like creature emerges from his head in the dead of night and slips away. After 2d6 days of gorging itself on the latent psychic energies of nearby creatures, it curls up into a ring-like shape and enters a torpor. It can remain in torpor for 1d4 years. If worn, it passes its eggs into the new host and dies, beginning the process described above.
While infested, a remove disease spell will grant the PC a Save vs. Rod. If successful, the parasite is expelled in a nosebleed of purple-black goo. All special powers vanish one turn thereafter.
Any sort of detection of thoughts will reveal a second set of thoughts, chattering and incomprehensible, along with the character's thoughts.
Although spell-like, none of these creatures abilities, nor any abilities it imparts on a host, are considered magical.
**This is brought to you by an immensely disturbing dream I had several years ago.