Deadly Hazard (Levels 1–4) or Nuisance Hazard (Levels 5–10)
Yellow mold grows in dark places, and one patch covers a 5-foot square. If touched, the mold ejects a cloud of spores that fills a 10-foot Cube. Any creature in that area must succeed on a DC 15 Constitution saving throw or take 11 (2d10) Poison damage and have the Poisoned condition for 1 minute. While Poisoned in this way, the creature takes 5 (1d10) Poison damage at the start of each of its turns. The creature repeats the save at the end of each of its turns, ending the effect on itself on a success.
Direct sunlight or any amount of Fire damage destroys a patch of yellow mold.