Some crazies are talking about building laser-born black holes from solar energy, then in turn using those to either power trans-solar travel, or to build more black holes. This is full of mad science with lines like:
A nuclear laser can convert on the order of 10^−3 of its rest mass to radiation, we would need a lasing mass of order one billion tons to produce the pulse. This should correspond to a mass of order 10 billion tonnes for the whole structure (the size of a small asteroid). Such a structure would be assembled in space near the sun by an army of robots and built out of space-based materials.