  Forbidden transitions between energy levels typically involve violation of
selection rules imposed by symmetry and/or conservation laws. A nanomagnet
tunneling between up and down states violates angular momentum conservation
because of broken rotational symmetry. Here we report observations of highly
forbidden transitions between spin states in a Ni$_4$ single-molecule magnet in
which a single photon can induce the spin to change by several times $\hbar$,
nearly reversing the direction of the spin. These observations are understood
as tunneling-assisted transitions that lift the standard $\Delta m = \pm 1$
selection rule for single-photon transitions. These transitions are observed at
low applied fields, where tunneling is dominated by the molecule's intrinsic
anisotropy and the field acts as a perturbation. Such transitions can be
exploited to create macroscopic superposition states that are not typically
accessible through single-photon $\Delta m = \pm 1$ transitions.
