  We investigate the microstructural and microrheological response to a tracer
particle of a two- dimensional colloidal suspension under thermodynamic
conditions close to a liquid-gas phase bound- ary. On the liquid side of the
binodal, increasing the velocity of the (repulsive) tracer leads to the
development of a pronounced cavitation bubble, within which the concentration
of colloidal parti- cles is strongly depleted. The tendency of the liquid to
cavitate is characterized by a dimensionless colloidal cavitation number. On
the gas side of the binodal, a pulled (attractive) tracer leaves behind it an
extended trail of colloidal liquid, arising from downstream advection of a
wetting layer on its surface. For both situations the velocity dependent
friction is calculated.
