Mercer class doomsday device

The Mercer class Doomsday Device is an exceptionally powerful Terran weapon, presumably developed by the Terran Confederacy. Its exact method of functioning is unknown but it appears to use a planet's own tectonic systems against it; creating a blast inside its core that sends volcanic ruptures to the surface (going by this assumption, it would only work on planets with a molten core). One such device was used to devastating effect on Wotan II.