  We investigate the cosmological attractor of the minimally coupled,
self-interacting phantom field with a positive energy density but negative
pressure. It is proved that the phantom cosmology is rigid in the sense that
there exists a unique attractor solution. We plot the trajectories in the phase
space numerically for the phantom field with three typical potentials. Phase
portraits indicate that an initial kinetic term decays rapidly and the
trajectories reach the unique attractor curve. We find that the curve
corresponds to the slow-climb solution.
