Initial surveys cataloged Kadambur as a garden world, perfect for human colonization, but the initial surveys missed a critical detail of the planet's ecology. It was not even detected by the initial colonists until after they had been on the planet for more than six months.
Spores of indigenous fungus-like lifeforms have strange interactions with the neurochemistry of off-world species.
In some cases, settlers formed close bonds with native animals – an empathy between sophont and beast that bordered on a gestalt or shared consciousness.
In other cases, humans regressed to animalistic behaviors. Typically, these were simply the behaviors of primates and early hominids, but at least one type of spore induced behavior that can only be described as rabid cannibalism.
Kadambur developed a truly alien culture that has limited contact with the other civilizations of the sector.