One of the lesser explored features of Dungeons and Dragons is disease. Below are some extra disease options for DMs to use in their campaigns. This set of diseases features a variant to regular disease – parasitic diseases.
When a creature finds themselves in a situation that causes a disease, they roll a d20 on the infection table. A roll of 1 on the disease table causes them to instead roll on the deadly disease table. A creature can have multiple diseases.
When To Use Diseases
Opportunities to infect players come up regularly in daily events or interactions with creatures. Perhaps the players are trudging their way through a swamp after a heated battle. You prompt them to make a Constitution saving throw to resist a disease entering through their wounds. Alternatively, a ravenous creature could infect a player with a savage bite. The method is up to you, but here are a few new diseases for you to try.
1 Roll on the deadly disease table.
2 The Roil – A crippling stomach virus that flares with activity. A creature afflicted with this disease must make a DC 12 Constitution saving throw at the start of each turn in combat. On a failure, they buckle over in pain and lose their choice of action or bonus action that turn. Lasts 1d4 days unless cured.
3 Lethargy – A disease that progressively saps the strength from its victim. A creature suffering this disease loses 5 ft. of their movement, cumulatively, at the start of each day. Lasts 1d6 days unless cured.
4 Hush – A throat infection that painfully inflames a creature’s vocal cords. Whenever a creature tries to speak or cast a spell with verbal components, they make a DC 12 Constitution saving throw. On a failure, the pain prevents them from speaking. Lasts 1d4 days unless cured.
5 Mudeye – Black, viscous fluid wells up in the eyes, causing burning irritation. A creature is afflicted with the blindness condition. Lasts 1d4 days unless cured.
6 Old Maid’s Burden – Sudden and acute arthritic pain lances through the joints. A creature’s AC is reduced by 2 for 1d6 days unless cured.
7 Fevermind – A persistent fever marked by sweating and feelings of confusion. An affected creature has disadvantage on ability checks and concentration checks. Lasts 1d6 days unless cured.
8 Hairy Eye – Bacterial growth in the eyes that wicks away moisture and causes blurred vision. A creature with this disease has a penalty to attacks equal to its proficiency bonus. Lasts 1d6 days unless cured.
9 Drowsy – A disease that saps the vitality from the body each day. A creature loses a number of hit points at the start of each day equal to twice their level. Lasts 1d10 + 1 days unless cured.
10 Rushing Fugue – When in perilous situations or combat, this disease briefly compels the infected individual to run. Once per hour, or at the start of every turn in combat, the creature makes a DC 12 Constitution saving throw. On a failure, it must use all of its movement to travel in a random direction. Lasts 1d4 days unless cured.
11 Sprinter’s Leg – A painful inflammation and swelling of the ankles and knees. A creature’s movement speed is reduced by 10 ft. for 1d4 days unless cured.
12 Swell – A dysfunction of the lymph nodes leading to a large swollen limb, usually an arm. A creature loses the function of that limb for 1d4 days unless cured.
13 Potbelly – A swelling of the stomach marked by loss of fluid retention and crippling abdominal pain. A creature with this disease requires twice as much food and water to sustain itself. Lasts 1d6 days unless cured.
14 Keratinosis – A rapid growth and hardening of the nails marked by a yellow and orange discoloration. A creature with this disease has difficulty grasping objects, causing disadvantage on weapon attacks, and cannot wear foot coverings. The creature may use the nails as a natural weapon, dealing 1d4 Slashing damage plus its Strength modifier on a hit.
15 Hyperphotosensitivity – A disease that causes extreme dilatation of the pupils. Creatures with this disease suffer the blindness condition in bright light, but can see normally in dim light. Lasts 1d6 days unless cured.
16 Daggerbones – A painful swelling and popping of the joints that weakens strength and reflexes. A creature with this disease has disadvantage on Strength and Dexterity checks and saving throws. Lasts 1d6 days unless cured.
The parasites found on the path are vicious and relentless. Effects that hamper or provide immunity to disease do not affect parasitic diseases. Spells such as Lesser Restoration do not remove the parasitic diseases.
17 Flashworm (Parasitic Disease)
A long, parasitic worm that inhabits a creature’s stomach. It eats until it grows too large and is violently regurgitated. While affected by this parasite, a creature does not gain any benefit from eating or drinking. Last 1d4 days unless cured.
18 Spiky Gut (Parasitic Disease)
Small parasites that lodge themselves in a creature’s colon. Intense activity while infected by these organisms causes great pain. A creature makes a DC 13 Constitution saving throw if it does the following:
- Makes an Athletics or Acrobatics check.
- Makes a Strength or Dexterity saving throw.
- Uses more than half of its movement in a single turn.
On a failure, the creature takes 1d4 piercing damage. Last 1d6 days until cured.
19 Moss Lung (Parasitic Disease)
These green parasites latch onto the moist lungs of a creature. A creature’s saliva turns bright green as they develop a terrible cough. While affected by these parasites, a creature cannot take the dash action. Additionally, on its turn, a creature may take either an action or bonus action on their turn, but not both. Lasts 1d4 days unless cured.
20 Sleeping Sickness (Parasitic Disease)
Parasites sap the strength from the body. During the first combat each day, an affected creature makes a DC 13 Constitution saving throw. On a failure, a wave of lethargy sweeps over the creature and it falls asleep for 1 minute. Another creature may use its action to wake the sleeping creature.
Deadly Diseases and Parasites
Rare and savage organisms that result in death if left untreated. Only powerful magic, such as the Greater Restoration spell, or rare natural remedies can cure these diseases.
1 Wasting Plague – A disease that eats away at muscle and sinew. At the start of each day, a creature’s maximum hit points are reduced by an amount equal to their level (CR) plus their Constitution modifier. This disease lasts until cured.
2 Brain Drain – Parasites that consume the fluid surrounding the brain. At the start of each day, a creature’s Intelligence score is reduced by 1. This disease lasts until cured.
3 Stonescale – A relentless virus that triggers the skin and muscle to calcify and turn to stone. A creature’s body begins to petrify and completely turns to stone after 1d6 + 4 days. This disease lasts until cured.
4 Hivemind – A rapidly evolving parasite that gains sentience at the end of its incubation. An infected creature is marked by a gradual black discoloration of its veins. Confusion and migraines wrack the creature’s mind. After 1d6 + 4 days, the infected creature’s consciousness is permanently replaced by the parasite. The parasite has access to all of the creature’s abilities. A writhing mass on the creature’s stomach pierces out with a sharp proboscis. This needle is used to infect other creatures when they are grappled. Can only be cured before the incubation period ends.