1. A black hole formed from energie. (They only exist in theory.)
2. Someone so hot that even science can't understand it.
When the 'planck temperature' (141,000 billion billion billion K) is reached and even more energie is added, instantly a black hole will be formed. Since the radiation emitted by the planck temperature has the smallest wavelength possible (1.616*10^-26 nano meters) adding more energie (increasing its temperature) would cause an effect unexplained by science, but is likely to be the creation of a kugelblitz.
1. I wonder if there is a kugelblitz in our galaxy.