Cobalt bomb

A cobalt bomb was an explosive device with greater destructive power than standard nuclear weapon.

A number of advanced races had access to cobalt bombs or the technology to create them. These included:
 * Qataka (NA: Timewyrm: Genesys)
 * Greld (MA: The Empire of Glass)
 * Waro (PDA: The Devil Goblins from Neptune)
 * Cybermen (NA: Iceberg)
 * Klytode (DWA: The Snag Finders)

Behind the scenes
Non-narrative information in DWBIT 47 stated that Daleks used cobalt bombs.