Grungs are aggressive froglike humanoids found in rain forests and tropical jungles. They are fiercely territorial and see themselves as superior to most other creatures.
Grung society is a caste system. Each caste lays eggs in a separate hatching pool, and juvenile grungs join their caste upon emergence from the hatchery. All grungs are a dull greenish gray when they are born, but each individual takes on the color of its caste as it grows to adulthood. From lowest to highest caste, grungs can be green, blue, purple, red, orange, or gold.
Grung poison loses its potency 1 minute after being removed from a grung. A similar breakdown occurs if the grung dies. A creature poisoned by a grung can suffer an additional effect that varies depending on the grung's skin color. This effect lasts until the creature is no longer poisoned by the grung.