  Multiple fields can become dynamical during the inflationary epoch. We
consider an example where a light field acquires isocurvature fluctuations
during inflation and contributes to the dark matter abundance at late times.
Interactions between the light field and the adiabatic sector contribute to
mixed adiabatic-isocurvature non-Gaussianity (NG). We show the resulting form
of NG has a different kinematic dependence than the 'local shape' commonly
considered, and highlight the parameter space where a dedicated search is
expected to significantly improve the current $\textit{Planck}$ sensitivity. We
interpret our results in the context of the QCD axion and illustrate how the
proposed NG searches can improve upon the existing searches for isocurvature
power spectrum and bispectrum.
