The Spartan Prometheus Assault Tank is a massive transport to both safely get your Space Marines across the battlefield and provide them with devastating fire support.

 It can be armed with sponson-mounted laser destroyers or gravis heavy bolter batteries, giving it a different loadout from the Spartan Assault Tank.

Rules for the Spartan Prometheus Assault Tank and Falchion Super-Heavy Tank Destroyer can be found in the Liber Astartes: Loyalist Legiones Astartes Army Book and the Liber Hereticus: Traitor Legiones Astartes Army Book.