Most dwarves would rather face a squad of orcs than confront a single rust monster. These strange, normally docile creatures corrode ferrous metals, then gobble up the rust they create. In doing so, they have ruined the armor, shields, and weapons of countless adventurers.
A rust monster's body is covered in thick, lumpy armor, its long tail ends in a bony protrusion, and two feathery antennae sprout from its insectile head.