This disease Targets Humanoids, although Gnomes are strangely immune. While in the grips of this disease, victims frequently succumb to fits of mad laughter, giving the disease its common name and its morbid nickname: “the shrieks.”
Symptoms manifest hours after infection and include fever and disorientation. The infected creature gains one level of Exhausted that can’t be removed until the disease is cured.
Any event that causes the infected creature great stress — including entering combat, taking damage, experiencing fear, or having a Nightmare — Forces the creature to make a DC 13 Fortitude. On a failed Contesting Roll, the creature takes 5 (1d10) Psychic damage and becomes Na with mad laughter for 1 minute. The creature can repeat the Contesting Roll at the end of each of its Turns, ending the mad laughter and the Na condition on a success.
Any Humanoid creature that stArts its Turn within 10 feet of an infected creature in the throes of mad laughter must succeed on a DC 10 Fortitude or also become infected with the disease. Once a creature succeeds on this Contesting Roll, it is immune to the mad laughter of that particular infected creature for 24 hours.
At the end of each Long Rest, an infected creature can make a DC 13 Fortitude. On a successful Contesting Roll, the DC for this Contesting Roll and for the Contesting Roll to avoid an Attack of mad laughter drops by . When the Contesting Roll DC drops to 0, the creature recovers from the disease. A creature that fails three of these Contesting Rolls gains a randomly determined form of indefinite madness, as described later in this chapter.