  I review the progress in research on intracluster planetary nebulae over the
last five years. Hundreds more intracluster planetary nebulae have been
detected in the nearby Virgo and Fornax galaxy clusters, searches of several
galaxy groups have been made, and intracluster planetary candidates have been
detected in the distant Coma cluster. The first theoretical studies of
intracluster planetaries have also been completed, studying their utility as
tracers of the intracluster light as a whole, and also as individual objects.
  From the results to date, it appears that intracluster planetaries are common
in galaxy clusters (10-20% of the total amount of starlight), but thus far,
none have been detected in galaxy groups, a result which currently is not well
understood. Limited spectroscopic follow-up of intracluster planetaries in
Virgo indicate that they have a complex velocity structure, in agreement with
numerical models of intracluster light. Hydrodynamic simulations of individual
intracluster planetaries predict that their morphology is significantly altered
by their intracluster environment, but their emission-line properties appear to
be unaffected.
