  We consider the strangeness-changing decays of hyperons into another baryon
and missing energy which is carried away by a pair of invisible spinless
bosons. Pursuing a model-independent approach and taking into account
constraints from the kaon sector, we find that these hyperon modes can have
large rates, especially if the bosons have parity-odd effective couplings to
light quarks. In that case the rates could attain values which are well within
the expected reach of the currently running BESIII experiment. Since the
branching fractions of hyperon decays with missing energy are tiny in the
standard model, observing them at ongoing or upcoming facilities would likely
be indicative of new physics. In addition, we show that the kaon restrictions
may be weakened or absent if the bosons have nonnegligible mass. Specifically,
if the bosons interact with the quarks solely via an axial-vector current, in
the mass region from about 115 to 175 MeV the constraints from rare kaon decays
no longer apply and a couple of the hyperon modes become the only direct probes
of such interactions. We also make comparisons with the previously explored
new-physics scenario where the invisible particles are spin-1/2 fermions.
