Have you thought about activating the "confusion" side effect whenever a Natural 1 is rolled instead? That way its a little more chaotic and randomised, the player might go for a session or three without it triggering and then suddenly have it impact whilst they do something such as haggling with a merchant, sneaking down a sewer etc.
Another option would be to use the Madness of Demogorgon table from Modrenkainens Tome of Foes to give the character a temporary madness/insanity effect to roleplay instead of the confusion effects.
I would likely also remove or reduce the damage and keep it like the curse on an Sword of Vengeance or give it a random option from the Bestow Curse spell or maybe do a reverse Lucky feat so you can get them to roll with disadvantage 3 times per long rest but its all largely dependant on the style of game you play and the characters hit points.
1) In my opinion the magic item described and the stated usage by the DM don't align. The item is extremely onerous. Only 10% of the time when they are "confused" in the 1d12 hours after the ritual are they acting normally. 30% of the time they attack whoever is closest. This does not match with the way you describe only having it come up occasionally. This will likely cause a problem at some point when the curse is discovered since it will suddenly get much worse in practice than you were running it.
2) The curse is so bad that if implemented as described, no one would ever choose to adventure with the character. They would cast greater restoration or get them taken to a temple to try to cure their madness. Standing staring, walking in random directions, attacking whoever is closest are actions of a madman.
3) I would instead suggest creating a magic item that fits both the spirit and implementation you are looking for PLUS providing some reason beyond sentimentality why the character would wish to keep it.
Eg
Amulet of the Demogorgon
Enclosing a piece of the flesh of the Demogorgon, this amulet forges a link between the wearer and the Demogorgon. At inconsistent intervals, the spirit of the Demogorgon may manifest causing brief periods of black outs for the wearer which they don't remember. During these periods their actions can appear confused. The amulet provides the benefits of an amulet of protection (+1 to AC and saves) and when identified this is the only property revealed.
Use your confusion table when you figure out what will trigger the curse. It could be situations of stress or distraction or you could use rolling a 1 or other game mechanics as suggested above.
The beneficial effect is due to the spirit of the Demogorgon reinforcing the spirit of the wearer. You could have the amulet emit a fiendish aura in the right circumstances or perhaps the wearer is prevented from entering hallowed ground. The beneficial effect motivates the player to keep it beyond the effects of the curse. They would be unlikely to consider giving up something so sentimental and beneficial.
I do like cursed items so kudos for having one!
Have you thought about activating the "confusion" side effect whenever a Natural 1 is rolled instead? That way its a little more chaotic and randomised, the player might go for a session or three without it triggering and then suddenly have it impact whilst they do something such as haggling with a merchant, sneaking down a sewer etc.
Another option would be to use the Madness of Demogorgon table from Modrenkainens Tome of Foes to give the character a temporary madness/insanity effect to roleplay instead of the confusion effects.
I would likely also remove or reduce the damage and keep it like the curse on an Sword of Vengeance or give it a random option from the Bestow Curse spell or maybe do a reverse Lucky feat so you can get them to roll with disadvantage 3 times per long rest but its all largely dependant on the style of game you play and the characters hit points.
Quick reply ..
1) In my opinion the magic item described and the stated usage by the DM don't align. The item is extremely onerous. Only 10% of the time when they are "confused" in the 1d12 hours after the ritual are they acting normally. 30% of the time they attack whoever is closest. This does not match with the way you describe only having it come up occasionally. This will likely cause a problem at some point when the curse is discovered since it will suddenly get much worse in practice than you were running it.
2) The curse is so bad that if implemented as described, no one would ever choose to adventure with the character. They would cast greater restoration or get them taken to a temple to try to cure their madness. Standing staring, walking in random directions, attacking whoever is closest are actions of a madman.
3) I would instead suggest creating a magic item that fits both the spirit and implementation you are looking for PLUS providing some reason beyond sentimentality why the character would wish to keep it.
Eg
Amulet of the Demogorgon
Enclosing a piece of the flesh of the Demogorgon, this amulet forges a link between the wearer and the Demogorgon. At inconsistent intervals, the spirit of the Demogorgon may manifest causing brief periods of black outs for the wearer which they don't remember. During these periods their actions can appear confused. The amulet provides the benefits of an amulet of protection (+1 to AC and saves) and when identified this is the only property revealed.
Use your confusion table when you figure out what will trigger the curse. It could be situations of stress or distraction or you could use rolling a 1 or other game mechanics as suggested above.
The beneficial effect is due to the spirit of the Demogorgon reinforcing the spirit of the wearer. You could have the amulet emit a fiendish aura in the right circumstances or perhaps the wearer is prevented from entering hallowed ground. The beneficial effect motivates the player to keep it beyond the effects of the curse. They would be unlikely to consider giving up something so sentimental and beneficial.