  A measurement of proton inelastic scattering of $^8$He at $8.25A$~MeV at
TRIUMF shows a resonance at 3.54(6)~MeV with a width of 0.89(11)~MeV. The
energy of the state is in good agreement with coupled cluster and no-core shell
model with continuum calculations, with the latter successfully describing the
measured resonance width as well. Its differential cross section analyzed with
phenomenological collective excitation form factor and microscopic coupled
reaction channels framework consistently reveals a large deformation parameter
$\beta_2$ = 0.40(3), consistent with no-core shell model predictions of a large
neutron deformation. This deformed double-closed shell at the neutron drip-line
opens a new paradigm.
