What if humans are biological weapons created by sentient machines, designed to terraform planets? The humans are "programmed" to remove trees, kill other organisms, paving the planet, change the atmosphere, and rebuild copies of the intelligent machines that sent them. These alien machines, essentially immortal, spread this biological weapon throughout the galaxy, having conquered the planet once the humans have killed off all biological life, including themselves, leaving behind a perfect machine utopia. Once the planet is secure the machines fire organism carrying satellites capable of seeding more planets with the ingredients for human evolution, thus continuing the spread of their domain.