  We study the invisible scalar of $S$ in charmed meson and baryon decays with
flavor-changing neutral currents (FCNCs) based on the model-independent
effective Lagrangian between the quarks and invisible scalar. From the bounds
of the coupling constants extracted from the recent BES III experiment on the
decay of $D^{0}\to\pi^{0}\bar\nu\nu$, we predict that the decay branching
ratios of $D^{+}\to\pi^{+}S$, $D_s^+\to K^+S$, $\Lambda_c\to pS$,
$\Xi_c^{0(+)}\to \Sigma^{0(+)}S$, and $\Xi_c^0\to\Lambda S$ can be as large as
$10.6,~2.53,~2.39,~0.963,~5.77$, and $2.92\times10^{-4}$ with $m_{_S}\approx
1.1~{\rm GeV}$, respectively. Some of these decay modes are accessible to the
ongoing experiments, such as BES III, LHCb and Belle II, as well as the future
ones, such as FCC-ee.
