Cackle Fever

Cheaply made potions and elixirs are sometimes tainted by Cackle Fever, which affects Humanoids only (gnomes are strangely immune). A creature suffers the following effects 1d4 days after infection:

• Fever: The creature gains 1 Exhaustion level, which lasts until the contagion ends on the creature.
• Uncontrollable Laughter: While the creature has the Exhaustion condition, the creature makes a DC 13 Constitution saving throw each time it takes damage other than Psychic damage. On a failed save, the creature takes 5 (1d10) Psychic damage and has the Incapacitated condition as it laughs uncontrollably. At the end of each of its turns, the creature repeats the save, ending the effect on itself on a success. After 1 minute, it succeeds automatically.

Fighting the Contagion

At the end of each Long Rest, an infected creature makes a DC 13 Constitution saving throw. After the creature succeeds on three of these saves, the contagion ends on it, and the creature is immune to Cackle Fever for 1 year.

Spreading the Contagion

Any Humanoid (other than a gnome) that starts its turn within a 10-foot Emanation originating from a creature infected with Cackle Fever must succeed on a DC 10 Constitution saving throw or also become infected with the contagion. On a successful save, the Humanoid can't catch the contagion from that particular infected creature for the next 24 hours.