Armor 14, Movement 60’, Hit Dice 1, 1 barbed leg attack 1d6 plus poison, 1 bite attack 1d4, Morale 9.
The skull crab lives alone in some remote swamp, forgotten underground region, or sea cave. It crawls around on chitinous, segmented legs and uses a decomposing head for a shell. Specialized musculature allows the crab to control the head’s jaw bone as a claw. Ocular stalks protrude from the hollowed out eye sockets. Depending on the crab’s age, the shell may still have rotting flesh attached or may just be a skull.
The skull crab reproduces by mating with your face. It knows who your true love is, and will assume that form. You must succeed in a save against magic or be taken in by the illusion and compelled to kiss it. If kissed, the crab will transmit a microscopic larva into the mouth of the new host. After transmission, the illusion fades.
You won't notice anything at first, but will complain of a growing headache over the next 2d12+12 days as the larva gestates and prepares to sever your head from your body. During the first third of this time, the larva can be killed by casting Cure Disease. It will slither out through the mouth, nose, or ear. After that, the larva has grown too large and must be removed surgically. If allowed to reach its full gestation period, the crab’s sharp legs will extend and slice the head clear of the neck.
This will kill the body, but your brain won't die. The skull crab feeds on living brain tissue, which it dissolves a little at a time. The host’s optical and auditory nerves are connected to the crab’s nervous system, so you can observe its surroundings while being helpless to act. You will also be aware of disappearing memories and diminishing brain function as more of the brain is consumed. In this way, the crab can live for hundreds of years.
Skull Crab Cult
Some of the few even aware of its existence consider the skull crab to be a divine vessel for preserving the brain after the usefulness of the body has been exhausted. Someone, often a powerful cleric or magic user, may allow herself to be infected with a skull crab larva. She then spends the gestation period in meditation while being tended to by other cultists. These cultists burn fragrant roots and herbs around the host and feed her tinctures and elixirs. All these have the cumulative effect of permitting the host’s brain control over the crab once gestation and bodily separation is complete. The host may move with the crab’s legs, speak with a rasping voice and cast spells. The crab will still slowly dissolve the host’s brain, however, and over decades or centuries this will drive the host quite insane.