  We show that phantom dark energy, if it is described by a K-essence theory,
has three fundamental problems: first, its hamiltonian is unbounded from below.
Second, classical stability precludes the equation of state from crossing the
``Lambda-barrier'', $w_\Lambda=-1$. Finally, both the equation of state and the
sound speed are unbounded -- the first, from below, the second, from above --
if the kinetic term is not bounded by dynamics.
