Rust Monster

A large, bug-like creature found in the depth of the Warren's mines. Excretions from antennae appear to dissolve known metals with scary efficiency. Younglings seem to hatch from large eggs, which does not require heat. Curiously, it gives off heat instead, and may get hotter close to hatching.
Other properties:

• chitinous shell

• large rust monster antennae forms into horns and has spikes