Numenera Discovery
Although creatures called ghost crabs exist in today's world, the Ninth World version is not related to them in any way. In fact, the unique abilities of the Ninth World ghost crabs suggest they might have been bioengineered, although for what purpose is anyone's guess.
Ghost crabs live on the ocean floor, typically in places that are at least 1 mile (1.5 km) deep. They can grow as large as 5 feet (1.5 m) across but average about 3 1/2 feet (1 m). Nimble hunters and intricate weavers, ghost crabs can build their silica webs along any jagged or uneven surface, including coral reefs, sunken ships, and ancient ruins. If no surface is available, they make one, killing large animals so they can build webs across the shells and bones.
Not true crabs, they are spiderlike creatures that spin hard shells from the same silica they use to build their webs. Ghost crabs appear and disappear in the depths as though shifting realms. Their webs, too, are often invisible unless one knows to look for the glinting, off-white strings.
Although ghost crabs are blind, their finely honed sense of touch allows them to hunt and devour anything that gets caught in their webs.
Motive: Hungers for flesh
Environment: Ghost crabs live alone or in pairs on the ocean floor.
Health: 20
Damage Inflicted: Moderate wound (6 points)
Armor: 6
Movement: Short
Combat: Ghost crabs wait patiently until a PC is tangled in the near-invisible strands of silica in
their web. As soon as the character is caught, the web begins its work, dehydrating the shell around the PC's DNA (dealing 3 points of damage per round for as long as they are caught).
While a victim is trapped, a ghost crab uses its giant front claws to tear the flesh from the living prey (6 points). If one of a crab's front claws is smashed or removed, it can spin another as a replacement, a process that takes two rounds.
Ghost crabs are immune to visual-based effects, such as illusions.
Use: The PCs are deep-diving in the ocean on a mission to recover treasure from a long-sunken construction site. While there, they notice ghostly creatures out of the corners of their eyes, scuttling through light and shadow. The characters might also find long, shining strands woven between the rotting underwater fixtures.
Loot: Silica webs and shells can be made into tools, rope, shields, and other useful items that usually have two to ten times the strength of a mundane item.
GM Intrusion: A PC damages or removes one of the ghost crab's front claws, causing the creature to quickly spin a new one. The new claw is nearly twice as large as the first, increasing the damage to 8 points.