The Necklace of False Awakening

The Awakening is the main religion in my world, so feel free to transpose this to whatever works for your campaign.
In the BFRPG campaign I'm running, this belonged to the psychotic cleric living in the catacombs among the deranged grave-robbers in the city of Sfera. Upon defeating him and his gang of thugs (which the players insisted were ghouls in the D&D sense, though in fact they were just normal humans of a ghoulish disposition) one of the party's clerics found it. A brilliantly shiny representation of an eye in the sun, which he recognized as the symbol of a somewhat archaic sect of the Awakening. Feeling the power flooding through the item, he put it on, and had an intense feeling of strength and mystical energy flooding through him.
The next time he took damage, however, he was forced to make a saving throw (Con based, as I'm not using traditional saves). When he failed, he felt an intense surge of energy and enthusiasm. He seemed to swell a little, his eyes bulged, and he began to sweat.
D6 and a D4. The D4 was applied as a modifier to the ability scores according to the D6 as follows.
1 + strength, - charisma
2 + dexterity, - intelligence
3 + constitution, - wisdom
4 + strength and dexterity, - charisma and intelligence
5 +strength and constitution, - charisma and wisdom
6 +dexterity and constitution, - intelligence and wisdom
The effect lasts 3d6 rounds, unless the saving throw roll was a natural 1, in which case it becomes permanent. Since the item qualifies as cursed, it cannot be removed. After one session playing with it, the player sees it as a tremendous benefit, since it strengthens him as a melee fighter, either with attack damage bonuses, hit points, or AC. As the party is low level (1-3, though the thief is closing in on 4th I think) cleric-as-melee is pretty standard, but when his wisdom drops below 9 permanently, he will lose all his clerical powers. Also, contemplating instituting some sort of madness from his ability scores getting knocked around so much.
I have a feeling that getting rid of this cursed item will be worth a quest or two.