Necrotic contamination spreads a magical undead disease that turns victims into the “living dead” (and eventually, if not cured, into the undead).

Infected (Stage 1): Whenever you take necrotic damage from any source, or from claw or bite damage from any undead, you must succeed at a Constitution saving throw with a DC equal to 8 + the damage dealt. If you fail, you are infected with a magical disease called the living death.

You take 1 level of exhaustion, your speed is reduced by 5 feet, and the wound begins to fester and weep blood and rancid pus. This gives you a -2 penalty to all Charisma-based skill checks for creatures who can see or smell your wound.

Infected (Stage 2): If you take additional necrotic or undead claw/bite damage and fail a second save against living death, you suffer 1 extra level of exhaustion, your speed is reduced by half, your skin turns gray, and you stink like a corpse. This causes you to suffer disadvantage on all Charisma-based skill checks.

Infected (Stage 3): If you take additional necrotic or undead claw/bite damage and fail a third save against living death, you take 1 extra level of exhaustion, and act as if poisoned due to the disease racing through your system. You are now covered head to toe in weeping bloody sores and dripping pus. This gives you a -10 penalty to all Charisma-based skill checks.

In Stage 3, you can no longer heal hit points normally, and must succeed at a DC 15 Constitution saving throw every day or lose 1 point of Constitution. Whenever your score reaches 0, you die and rise as a ghast in 1d4 rounds if you had 4 or more levels, or as a ghoul if you had less. You become undead if you die by any means, not just from the living death.

Cure: You need a greater restoration or heal to free yourself from living death. If these spells are unavailable, then as long as you consume a gallon of fresh humanoid blood or consume a pound of fresh humanoid flesh (or some combination of the two), or if you bathe in holy water for 1 hour, you automatically make your saving throw that day. However, every time you fail a save against living death afterward, you lose 2 points of Constitution instead as the disease accelerates.

Duration: This contamination continues in you even after you exit this terrain, and even after you destroy or defeat the primary monster, villain, or relic (etc.) that created the living death.