Arakis's zombie problem went largely ignored, because it was believed that the Shai-Hulud (sand worms) would effectively dispose of the undead walkers. Unfortunately the problem grew until the roving herds of sunburnt ghouls threatened the flow of spice. While observing one of the great reanimated masses over take a Harvester from the safety of an ornithopter, an Imperial Zoologists noted that the sand caked flesh eating revenants walked entirely without rhythm.
Shortly after receiving this report the Bene Gesserits claimed to have a solution to Arakis's hellish resurrections. They asserted to the agents of the great houses that the worms could be drawn to the walkers using an ancient sonic weapon. According to the sisters, exposing the zombies to an antediluvian ballad composed by the great master M. Jackson would force them to step in time.
One of the PCs comes across a magical ring that grants some power but has odd aura as if cursed. Yet this curse is different than the standard curse. When the PC puts on the ring he/she suddenly feels married. There is now an illusionary woman, who he/she cares deeply for but who is also always very critical of the PC. The wife is demanding of attention and constantly giving the PC directions. The PC wearing the ring is the only one that can see and hear the bride. The curse can never completely be lifted. Even if the PC takes off the ring and somebody else puts the ring on; the PC will still be visited by the ex-wife at least once a month. During this visit she will demand money and apologies.
As population increases, animal souls are promoted to human before they are spiritually advanced enough in terms of impulse control, etc.: this shouldn't have happened, but karmic progression is automatic, after all--it's a force of nature. But the 'animalization' of humankind bodes ill for civilization.
No doubt the same goes for elves, dwarves, and so on.