Infested: Parasites For Your Game

There are thousands of ways to die, millions if you’re creative. I would take any of them over that.”

– Kinsey Stafford, Apprentice Field Medic

Adventurers go to great lengths to put themselves where they don’t belong. Traversing far-off mountains, exploring dense jungles, or crossing shifting deserts means risking many dangers – both seen and unseen. And although facing the ravenous beasts and evil hordes that call these wild places home is a terrifying prospect, sometimes the gravest threats these areas contain come in the smallest packages. 


Parasites introduce a new play element into your games to challenge (and disgust) your players. Whereas diseases in a fantasy medieval game can be blanketed in the comfort of ignorance, since the knowledge of viruses and bacteria is typically nonexistent in these settings, there’s no getting around the mental ramifications that come along with a body being infested with parasites. Beyond the painful and grotesque physical symptoms, these tiny scourges can also bring feelings of invasion and violation that players must overcome. 

Parasites bring a new condition along with them – infested. Unless otherwise stated in the Parasite effect description, any spell or effect that ends a condition will end being infested as well.


  • An infested creature has disadvantage on Constitution saving throws and Wisdom (Perception) checks.


Any character who has proficiency with an Herbalism Kit can create a single dose of a basic antiparasitic during a long rest if the materials are available. Some parasites are more exotic, virulent, or magical than others, and require one or more special materials in order to make an effective antiparasitic to prevent or treat their infestation. If special materials are necessary, they will be listed in the description of the parasite. 


Adventuring Gear

50 gp

This potent tincture provides a creature with advantage on saving throws against infestation for 1 hour or ends the infested condition in a currently affected creature.


Particularly adventurous characters can attempt to harvest parasites for later use. Parasites can be harvested using the same standard rules as harvesting poison. 

Types of Parasites

The following are a few different parasites that you can introduce into your games and can also be used as templates for creating your own parasites for later use.

Dream Eaters (Internal)

Dream Eaters are small leech-like creatures that inhabit deserts and sandy beaches. They spend most of their lives in hibernation among the dunes, only waking when they sense the presence of a warm-blooded creature in their vicinity. Those unfortunate enough to make camp among the Dream Eaters stir these parasites from their slumber, causing the worms to slowly climb from the sands and make their way up and into their victim’s ear canal. By the next morning, the throbbing pain in the affected creature’s ears combined with the constant scritching of the Dream Eater’s movements makes sleep and concentration almost impossible. 

Effect: Dream Eaters cause incessant pain and irritation in the ears of those they afflict. A creature subjected to this parasite must make a DC 13 Constitution saving throw. On a failed save, it is infested for 2d4 days, has disadvantage on any ability checks that require hearing and cannot complete a long rest. On a successful save, the creature is infested for 2d12 hours. 

Storm Mites (External)

Storm Mites are aquatic arthropods roughly the size and shape of a copper piece. In most circumstances, these creatures remain in the shallow tidal pools where they’re born without ever coming into contact with people. However, during periods of monsoons and flooding Storm Mite larvae are swept inland, where they burrow under the skin of anyone that they touch. They create large, excruciating boils wherever they gather on their victim, making it almost impossible to wear anything heavier than a loose tunic. After they’ve finished incubating within their host, the immature mites burst out of the creature’s flesh, causing even more trauma and turmoil. 

Effect: Storm Mites burrow into the skin, causing painful and grotesque boils. A creature that comes into contact with this parasite must make a DC 15 Constitution saving throw. On a failed save, the creature is infested for 1d6 days while the mites incubate. During this period, the pustules caused by the incubating mites make wearing light, medium, or heavy armor impossible. At the end of their incubation period, the mites burst from their host’s skin, causing 3d4 damage. 

Hermit Hounds (Internal)

Hermit hounds are thin, translucent worms that are found infesting the waters and wildlife of forested areas. Incredibly difficult to see, they’re most commonly encountered by novice adventurers and careless rangers who improperly prepare game or water tainted with the parasite. After infestation, Hermit Hounds cause a noticeable change in the personality of their host, making them prone to irritation and paranoia, and driving them to become more and more isolated. Once driven into seclusion in the wilderness, the host most typically falls victim to another wild animal or monster that the Hermit Hounds then pass on to. 

Effect: Hermit Hounds cloud the mind and dull their host’s personality. A creature that drinks water or eats food contaminated with this parasite must make a DC 14 Constitution saving throw. On a failed save, the creature is infested for 1d10 days and has disadvantage on all Charisma saving throws and ability checks.  

Wraith Kin (External)

Wraith Kin are tiny, transparent jellies that dwell in caves and dank dungeons throughout the realms. They wait on floors, walls, and ceilings in a dormant state until a living creature passes near them, rousing them from their slumber, at which point they attach themselves to their host’s flesh. The impact of the Wraith Kin can be noticed immediately on their host, who find themselves suddenly depleted of their vitality and life force. Given their near-invisible bodies and the draining effects that they have on those they infest, they are rumored to actually be a type of undead, though this is yet to be proven. 

Effect: Wraith’s Kin attach to their host’s flesh, leeching their energy and spirit. A creature whose flesh comes into contact with Wraith Kin must make a DC 13 Constitution saving throw or be infested for 2d6 days. While infested, the creature’s hit point maximum is reduced by 4d4.

Featured Image: Dream Eater by Anderson Maia

You can download this free PDF on DriveThruRpg.

Let us know what you think of this supplement in the comments below!

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