  Using numerical methods we present the first full nonlinear study of phantom
scalar field accreted into a black hole. We study different initial
configurations and find that the accretion of the field into the black hole can
reduce its area down to 50 percent within time scales of the order of few
masses of the initial horizon. The analysis includes the cases where the total
energy of the space-time is positive or negative. The confirmation of this
effect in full nonlinear general relativity implies that the accretion of
exotic matter could be considered an evaporation process. We speculate that if
this sort of exotic matter has some cosmological significance, this black hole
area reduction process might have played a crucial role in black hole formation
and population.
