the Ogre Magi's Ring

Ogre Magi get all the cool magical powers:

1. Fly (12trns)
2. Invisibility
3. Darkness (1"rad)
4. Polymorph (humanoid, 4-12')
5. Regenerate (1HP/r)
6. Charm Person
7. Sleep
8. Gaseous Form
9. Cone o' Cold (8d8)
10. (Ogre Strength; 18/00)

What if there were a Magic Item, maybe a Ring, that would grant all the abilities & powers of an Ogre Magi? Quite a powerful item... brought to mind the 'Ring of Gaxx', with the "randomly resetting" rotating gemstone, so how about:

The Ring of the Ogre Magi is set with a white gem of nine (or ten, if you incl Ogre STR) facets, each keyed to one of the magical functions, each usable 1/day, but here's the kicker; only one function may be in effect at any time. If the gem is set to Charm Person, the Charm ends when another function is selected, and the gem is turned until a different facet faces the tiny ruby triangle set into the band... if you encounter a barred passage, do you forgo your Polymorph disguise for Ogre Strength, and try to Bend Bars, or do you switch to Gaseous Form to slip through, and save the STR for later combat?...

Somebody's PC just acquired a major arsenal of a Magic Item, so of course there's a catch, right?

Immediately upon putting it on, it permanently drains 1d4 HP, and grafts to the digit for life

Changes to the physiology occur:
-Eyes change color (the MM reads, "Their eyes are dark pupiled with a white center." Does this mean a dark iris and a white pupil? You decide. Maybe throw in Infravision as a full-time bonus)
- Sure you Regenerate, but Magical Healing no longer works on you; no Cure Spells, no Healing Potions, just natural rest and the ring, baby. You're gonna have to set aside some time for your Precious ea day! (And remember - you can Regenerate for as long as you want, but once you switch facets, no more healing for 24hrs!)

Since this gimcrack does damn near everything, no other Magic Rings for you. In fact, I'd even say that any Item under 'Misc. Magic' simply would no longer work for the ring-bearer, or perhaps only those the DM allows.

Other "side-effects" occur: Ogres tend to like/hate you, an Ogre Magi is searching for the Ring, which contains the spirit of his father, must defeat him in single combat (I don't know... somehow or other!), maybe use of the Ring gradually adds further Ogrish physical attributes...

I love the idea of this Item being found as per The Hobbit; just lying there on the ground in an untraveled area, no guards, no Big Boss Battle, not even a locked chest - just right there on the floor, in a dark corridor. And so are destinies made and fortunes assured.