New Prysmos

Existing deep in Cybertron's underground, New Prysmos is a fragment of the lost world of Prysmos recreated through the power of the Talisman. Little more than a scrap of city compared to the grand metropolises of their lost homeworld, its cramped conditions have led some of the Prysmosians who inhabit it to compare it to a refugee camp.

Fiction

IDW Generation 1 continuity

Prysmos was once a world where magic ruled, until the technophobic sorcerer Merkynn who had orchestrated the rebirth of magic across his planet accidentally prompted the destruction of the world as its three suns moved out of alignment. Hoping to find a new world to colonize, he found his way to Earth shortly before World War II, where he disguised himself as "Garrison Kreiger". First Strike #6

When Joe Colton came to Kreiger for aid in ending the Cybertronian threat to Earth through usage of the mysterious Talisman, First Strike #0 Kreiger saw the chance to use the Talisman to terraform Cybertron into a reborn copy of Prysmos.

The resistance he faced prompted him to activate the Talisman prematurely, only managing to transform a small portion of the planet into "New Prysmos" which he claimed would be the staging ground to wipe away all technology from the galaxy and bring about a new "Age of Magic".

Reflecting on the situation, Scarlett observed that New Prysmos' creation had caused a substantial energon drain which, ironically, made the Cybertronians need their alliance with Earth, and the victory was bittersweet as a result. Cybertronian Security Forces investigated the energy field around New Prysmos, but were unable to penetrate it. First Strike #6

After attending Sideswipe's funeral, Kup went off to investigate the underground city. The Dead Come Home, Part 1