Massive spinning particles leave imprints on primordial non-Gaussianity via their coupling to the inflaton, even despite their exponential dilution during inflation. Improving on modern Cosmological Bootstrap techniques I present a search for these particles using the redshift-space galaxy power spectrum and bispectrum multipoles measured in BOSS, the first analysis of such kind with cosmological data. I focus on spin-0 particles in the principal series and constrain their couplings to the inflaton at varying speed of propagation and mass, marginalizing over the unknown inflaton self interactions. This is a fundamental step towards inflationary spectroscopy from cosmological observations, the ultimate link between the physics of the infinitely large and infinitely small.