Reports detection, 15 October 1991, of a single air shower with reconstructed primary energy 3.2 +/- 0.9 x 10^20 eV (~51 J) by the Fly’s Eye detector — the “Oh-My-God particle,” the highest-energy cosmic ray then recorded, well above the expected GZK cutoff. Center-of-mass energy for a proton-proton-equivalent interaction with this primary vastly exceeds the LHC’s 14 TeV. relevance_note: the canonical single-event anchor for “nature already exceeds LHC collision energies by many orders of magnitude.”