  The recent Belle II observation of $B \to K E_{\rm miss}$ challenges
theoretical interpretations in terms of Standard Model neutrino final states.
Instead, we consider new physics scenarios where up to two new light-invisible
particles of spin 0 up to 3/2 are present in the final state. We identify
viable scenarios by reconstructing the (binned) likelihoods of the relevant $B
\to K^{(*)} E_{\rm miss}$ and also $B_s \to E_{\rm miss}$ experimental analyses
and present preferred regions of couplings and masses. In particular, we find
that the current data prefers two-body decay kinematics involving the emission
of a single massive scalar or a vector particle, or alternatively, three-body
decays involving pairs of massive scalars or spin 1/2 fermions. When
applicable, we compare our findings with existing literature and briefly
discuss some model-building implications.
