The alchemist's cats

This is a closed species.

You've heard the story of how a cat can steal a baby's breath, and so has our Alchemist. 

But if they can steal breath - why not other elements? That is why he created these cats.

An Eco warrior bent on helping the planet recover of mankind's influence, he will send his cats as a cleanup crew to help nature.

When created, these robotic cats are programmed to assimilate an element, and before sending them off a shutoff function and condition is required and coded in.
EG, Nickel will shut off after the nickel in a certain radius is removed.