Planar Bestiary
A scourge of metal mines across a host of worlds, iron locusts are a blight to industry. To civilizations that require metal to survive, human-sized iron locusts—which multiply as they ingest iron—are a death sentence.
Built to fix the damage of complex mechanical devices in a distant dimension, the self-repairing iron locusts grew beyond their original instructions. Without their initial constraints, and instead mimicking regular life in their metallic fashion, iron locusts consumed the works of their original builders, then began to multiply and go forth.
Normally iron locusts operate far from each other, having a basic understanding that their ability to split into more versions of themselves creates competition for nearby metal. However, sometimes too many iron locusts are born in close proximity anyway. When this happens, they embrace it and multiply far beyond their normal limit. Using a group intelligence that arises only in their swarm state, they open a portal to a new world of the Material Plane, one rich in metal, to spread out upon and ingest.
Motive: Hungers for metal
Environment: Anywhere in the multiverse near metal concentrations, alone, in loose groups of three to five, or in great swarms
Health: 6
Damage Inflicted: Moderate wound (4 points); see Combat
Armor: 3
Movement: Short; short when climbing or flying
Modifications: Climbing as level 6
Combat: An iron locust either bites, saws, batters, or claws a target, depending on their particular conformation, dealing 2 points of damage plus 2 points of damage from electricity. These attacks are eased against creatures wearing a lot of metal, such as metal armor.
As their action, the locust can attack a metal object, causing it to flow like water and join the locust's metal body, restoring 3 points of health. The locust can affect a ferrous metal object up to a 1-foot (30 cm) cube in size (or excavate a cavity 1-foot (30 cm) cube in size in a larger metal object).
If an object the locust wants is being worn or carried by a creature, the iron locust attacks the creature. If the attack hits, the creature takes damage and must succeed on another Speed defense task or one metal object they carry (such as armor, a shield, or something else) descends one step on the object damage track. Each additional successful attack pushes it another step down the damage track, until the object is destroyed.
Electricity heals an iron locust equal to the amount of damage the electrical attack would inflict.
A locust divides if they regain 6 more points of health than their maximum, becoming two separate iron locusts with 6 points of health.
Interaction: Insect-like in their single-mindedness, it's impossible to negotiate with an iron locust, and difficult to drive them off.
Use: The dwarf smith's shipment of iron contains two iron locusts. That's bad enough, but does that mean the mine from which the shipment came is infested?
GM Intrusion: When the locust attacks, a character's cypher with a metallic component is activated in a way that hurts or distracts the character or the character's allies.