  We systematically analyze the flavor color spin structure of the pentaquark
$q^4\bar{Q}$ system in a constituent quark model based on the chromomagnetic
interaction in both the SU(3) flavor symmetric and SU(3) flavor broken case
with and without charm quarks. We show that the originally proposed pentaquark
state $\bar{Q}s qqq$ by Gignoux et al and by Lipkin indeed belongs to the most
stable pentaquark configuration, but that when charm quark mass correction
based on recent experiments are taken into account, a doubly charmed
antistrange pentaquark configuration ($udc c \bar{s}$) is perhaps the only
flavor exotic configuration that could be stable and realistically searched for
at present through the $\Lambda_c K^+ K^- \pi^+$ final states. The proposed
final state is just reconstructing $K^+$ instead of $\pi^+$ in the measurement
of $\Xi^{++}_{cc} \rightarrow \Lambda_c K^- \pi^+ \pi^+$ reported by LHCb
collaboration and hence measurable immediately.
