  Interatomic Coulombic decay (ICD) plays a crucial role in weakly bound
complexes exposed to intense or high-energy radiation. So far, neutral or ionic
atoms or molecules have been prepared in singly excited electron or hole states
which can transfer energy to neighboring centers and cause ionization and
radiation damage. Here we demonstrate that a doubly excited atom, despite its
extremely short lifetime, can decay by ICD; evidenced by high-resolution
photoelectron spectra of He nanodroplets excited to the 2s2p+ state. We find
that ICD proceeds by relaxation into excited He$^*$He$^+$ atom-pair states, in
agreement with calculations. The ability of inducing ICD by resonant excitation
far above the single-ionization threshold opens opportunities for controlling
radiation damage to a high degree of element specificity and spectral
selectivity.
