Triptych Mask

The three-faced Triptych Mask, or Onyx Triptych, of Onyx Prime allows him to see other times, places, souls, and even the afterlife.

Fiction

The Covenant of Primus

The Triptych Mask was given to Onyx by Primus himself. After Onyx had merged with the Core, Primus used the mask to scan all life in the universe as a template for the Cybertronian species. Though the results were mostly bipedal, the mask allowed for the birth of a large diversity of new Cybertronians. The Covenant of Primus

IDW Generation 1 continuity

Alpha Trion named the Onyx Triptych as one of the artifacts and weapons belonging to the Primes, along with the Enigma of Combination and the Star Saber, regarding them as "metaphors made real" that were unbeatable by 'ordinary' Cybertronians. Aphelion