  We give a detailed calculation for the Hamiltonian of single galileon field
theory, keeping track of all the surface terms. We calculate the energy of
static, spherically symmetric configuration of the single galileon field at
cubic order coupled to a point-source and show that the 2-branches of the
solution possess energy of equal magnitude and opposite sign, the sign of which
is determined by the coefficient of the kinetic term $\alpha_2$. Moreover the
energy is regularized in the short distance (ultra-violet) regime by the
dominant cubic term even though the source is divergent at the origin. We argue
that the origin of the negativity is due to the ghost-like modes in the
corresponding branch in the presence of the point source. This seems to be a
non-linear manifestation of the ghost instability.
