Some gastropods of Zereth Mortis have inexplicably metallic shells. These are generally--and inexplicably--bronze, indistinct from the metal any novice mortal miner might work, save that no mortal labor could craft this living creature.
Lihuvim hastily created many of these creatures to assist it in a crisis. Though its original designs were unstable and doomed, it has since perfected the design and is willing to share it with mortals.
This creature was not designed by the First Ones, but instead by an unknown being attempting to create a very fast runner. Needless to say, the attempt failed.