Question

I need ONE MORE non-living thing that metabolizes. I already have Viruses and Cars.

Answer 1

I believe you could use FIRE.

we consider an organism had metabolizing capability if it manage to absorb nutrients from substance, and secrete it.
Fire has similar feature with this (for example, if it got near woods, fire will consume the woods and got bigger from it, and secrete ash after it done)

Answer 2

Try Tree I hope this helps