Wear it intact — you're just a person wearing a weird mask.
The helmet breaks (durability hits 0, tracked via an advancement that fires on the exact break) → the curse permanently awakens. You become a Stone Vampire: permanent Night Vision, Speed IV, Strength V, faster regen at night — but you catch fire every tick you're standing in direct daylight, unless you're in water or have Fire Resistance. This is irreversible in this build, matching the "no going back" tone of the source.
