  We discuss a class of phantom ($p < - \varrho$) cosmological models. Except
for phantom we admit various forms of standard types of matter and discuss the
problem of singularities for these cosmologies. The singularities are different
from those of standard matter cosmology since they appear for infinite values
of the scale factor. We also find an interesting relation between the phantom
models and standard matter models which is like the duality symmetry of string
cosmology.
