Vanishing Plague (5e Disease)
From D&D Wiki
This disease progresses in stages, and is often caught in forests with a high concentration of magic. You must make a Constitution save with a DC of 12 to avoid infection.
Stage 1: The first symptoms appear after 1 hour. The afflicted becomes slightly translucent and loses 1 Strength. This Strength returns once the disease ends. Every day, the afflicted must make a Constitution save with a DC of 12. After 3 successes, the disease ends. On a single failure, the disease progresses to Stage 2.
Stage 2: The afflicted becomes noticeably translucent and loses a further 1 Strength. They have a hard time holding onto things, and whenever you miss on an attack roll, you drop your weapon. At this point onwards, each stage progresses by 1 stage every day until the disease is cured.
Stage 3: The afflicted is now so translucent they are hard to see when unclothed, and lose a further 1 Strength. They gain advantage on Dexterity (Stealth) checks while naked, and resistance to bludgeoning, piercing, and slashing damage from nonmagical attacks.
Stage 4: At this point, the afflicted is completely invisible, and they lose a further 1 Strength. They are incapable of making unarmed strikes as any attempt simply feels like a breeze. They also gain immunity to bludgeoning, piercing, and slashing from nonmagical attacks, but they cannot equip nonmagical armor as it simply falls off of them.
Stage 5: Upon reaching Stage 5 and every day onwards, the afflicted loses 1d4 Strength each day.
If at any point, the victim falls below 0 Strength, they disappear entirely. The disease lingers in the area around where they disappeared; this is the only method the disease spreads. As they leave no body, they can only be revived with a true resurrection or wish spell.
Dispel magic can temporarily alleviate the effects of the disease and make the afflicted wholly visible and tangible for 1 hour. The cure for Vanishing Plague is a cream made from glowing mushrooms which must coat the entire body.