The Stars are Fire
Tiny nanomachines can be incredibly useful tools. But they can also become a terrible threat. Like cells in a living body that develop cancer, these out-of-control self-replicating robots can consume everything in their path while building more of themselves. A typical swarm is about 6 m (20 feet) in diameter, individually consisting of millions of individual minuscule machines. However, several swarms can act together, creating a much larger cloud of death with just one purpose: to eat and replicate. Able to move large distances by gliding through the air, cloud-like swarms take on intriguing shapes and ripple with mathematical patterns as they approach a potential target, beautiful and deadly.
Ecophagic swarms sometimes build weird structures or artifacts in the wake of their feeding, like massive metallic ant or wasp mounds, or something without any reference at all in the natural world.
Motive: Hungers for matter, including flesh
Environment: Ecophagic swarms are drawn most to areas rich in rare-earth metals, such as large cities or space stations where everyone carries a smartphone, AR glasses, or something similar (Space)
Health: 12
Damage: 4 points
Movement: Flies a long distance
Combat: As a mass of countless tiny machines, an ecophagic swarm can flow around obstacles and squeeze through cracks large enough to permit a single sub-millimeter machine. That includes over and around other creatures. Characters touched by a leading edge-or wholly enveloped within the hazy "body"-of an ecophagic swarm must succeed on a Might defense task or take 4 points of damage. If the character doesn't wear armor of some kind, they take 1 point of damage even if they succeed.
For its part, an ecophagic swarm ignores any attack that targets a single creature (unless it's an electrical attack), but it takes normal damage from attacks that affect an area (and electrical attacks), such as a detonation. A swarm cannot enter liquids, unless it takes about an hour to build new subunits that are aquatic.
Interactions: Someone with an ability to communicate with machines might be able to interact with a swarm. Even then, attempts to influence it are hindered by three steps.
Uses: A promising new nanotech "printing" technology was hacked by radical elements
GM Intrusion: The character must succeed on a Speed defense roll or their armor (or other important piece of equipment) is taken by the swarm.