  The motion of a massive test particle in a Schwarzschild spacetime surrounded
by a perfect fluid with equation of state $p_0= w \rho_0$ is investigated.
Deviations from geodesic motion are analyzed as a function of the parameter
$w$, ranging from $w=1$ which corresponds to the case of massive free scalar
fields, down into the so-called "phantom" energy, with $w<-1$. It is found that
the interaction with the fluid distribution leads to capture (escape) of the
particle trajectory in the case $1+w>0$ ($<0$), respectively. Based on this
result, it is argued that inspection of the trajectories of test particles in
the vicinity of a Schwarzschild black hole may offer a new means of gaining
insights into the nature of cosmic matter.
