Humans developed a new weapon:
Black hole launcher.
How it works:
A mobile particle acelerator acelerates two particles to huge speeds and collide both. A mini black hole is created. The mini black hole flies throughout a barrel containing a magnetic field, again accelerating (the original particles where of the same charge) towards outside the weapon, while the weapon barrel contains pieces of material with high neutron absorption cross section, intended to feed the black hole. The idea is to have a anti-planetary weapon. If the black hole enters the planet core it will slowly consume the planet to nothingness.
Is it feasible? How long would take to consume the planet? If the two particles being collided are of the same charge, will the black hole keep the charge? Can a small black hole be contained magnetically (if charged)? Can it be fed with pieces of material dense enough to increase the probability of the black hole hitting something? If fed, how big does it need to be to have a certainty of hitting ordinary matter crossed by it (i.e. matter of the targeted planet - earthlike)?