Swamp Monster

Large beast, unaligned

Armor Class 14 (natural armor)
Hit Points 76 (8d10+32)
Speed 20 ft., swim 40 ft.

STR	DEX	CON	INT	WIS	CHA
20 (+5)	17 (+3)	18 (+4)	2 (-4)	12 (+1)	5 (-3)

Skills Perception +3, Stealth +5
Damage Immunities poison
Senses passive Perception 13
Languages –
Challenge 3 (700 XP)

SPECIAL TRAITS

• Hold Breath. A swamp monster can hold his breath for 1 hour.
• Spore-splosion. When a swamp monster dies, it’s corpse explodes with a burst of spores. Each creature within 50 feet of him must make a DC 15 Constitution saving throw, becoming infected with umamish on a failed save.

ACTIONS

• Bite. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 14 (3d6+5) piercing damage plus 4 (1d6) poison damage and the creature must make a DC 15 Constitution saving throw or become infected with umamish.

Umamish Infection

Umamish are unique among fungi as they are the only parasitic fungus known to have gained sentience. These parasites extract their host’s nutrients while invigorating the victim to keep it alive long enough to spread further spores. When a beast or humanoid creature is exposed to umamish spores, it must make a DC 15 Constitution saving throw or become infected.

It takes 1d4 days for the infection’s first symptoms to manifest in an infected creature. The umamish then grow slowly and their rate of growth varies greatly depending on their host.

Whenever the infected creature advances in a class level, their umamish infection progresses to the next stage (if running this adventure as a short self-contained quest, progress the infected PC immediately to stage 4 infection when they wake the following day.) For NPCs or creatures without class levels, umamish infection progresses to the next stage automatically every 1d4 weeks. If the infected creature spends the majority of its time in a damp and dark environment such as a cave, swamp, or dungeon, its infection progresses to the next stage every 1d2 weeks.

• First Stage. First stage symptoms include warty growths and a persistent rash that covers most of the back and shoulders. The infected creature regains only half the normal number of hit points when spending Hit Dice during short rests as the fungal infection siphons off its vitality. The umamish also act as a blood filter for their host, giving the infected creature immunity to poison damage and all other nonmagical diseases.
• Second Stage. At the second stage of infection the umamish sprout as full mushroom caps with eyes and mouths, gaining the ability to speak and understand any language their host knows. The umamish lie and plead with their host to keep them “happy” about their presence, presenting themselves as “symbiotic.” The umamish make Charisma (Persuasion) and Charisma (Deception) checks with a +8 bonus. As the mushrooms intertwine with a substantial amount of muscle tissue, the infected creature gains a +2 bonus to both its Strength and Constitution ability scores.
• Third Stage. At the third stage of the infection, the umamish fully integrate into their host’s nervous system. The infected creature gains a +2 bonus to its primary spellcasting ability score (or Dexterity if the infected creature does not have the Pact Magic or Spellcasting features). The umamish also become constantly aware of the infected creature’s surface thoughts as per the spell detect thoughts.
• Fourth Stage. At the fourth and final stage of infection, the umamish attempt to control the mind of the infected creature and spread their spores. The infected creature becomes charmed by the umamish as per the spell geas, and it is compelled to infect other creatures with umamish spores and to take infected creatures to damp dark places. Whenever the infected creature hits another creature with a melee attack, that attack deals an additional 3 (1d6) poison damage and the creature must make a DC 15 Constitution saving throw or become infected with umamish. In addition, when the infected creature dies, its corpse explodes with a burst of spores. Each creature within 25 feet of it must make a DC 15 Constitution saving throw, becoming infected with umamish on a failed save.

For every size category larger than Medium the infected creature is, the radius of this trait doubles.

Curing Umamish Infection

An umamish infection is extremely difficult to cure and normal medical and magical means such as the lesser restoration and greater restoration spells are ineffective, as is a paladin‘s Lay on Hands.

Umamish are still acting as a blood filter for their host, however, and they can be overloaded by particularly strong toxins. The infected creature is immune to poison damage, but when this immunity would prevent the infected creature from taking 20 or more poison damage from a single attack, the umamish infestation withers away and the creature fully recovers from the disease.