  Many non-minimal dark matter scenarios lead to oscillatory features in the
matter power spectrum induced by interactions either within the dark sector or
with particles from the standard model. Observing such dark acoustic
oscillations would therefore be a major step towards understanding dark matter.
We investigate what happens to oscillatory features during the process of
nonlinear structure formation. We show that at the level of the power spectrum,
oscillations are smoothed out by nonlinear mode coupling, gradually
disappearing towards lower redshifts. In the halo mass function, however, the
same oscillations remain visible until the present epoch. As a consequence,
dark acoustic oscillations could be detectable in observations that are either
based on the halo mass function or on the high-redshift power spectrum. We
investigate the effect of such oscillations on different observables, namely,
the cluster mass function, the stellar-to-halo mass relation, and the
Lyman-$\alpha$ flux power spectrum. We find that dark acoustic oscillations
remain visible in all of these observables, but they are very extended and of
low amplitude, making it challenging to detect them as distinct features in the
data.
