A dalekanium bomb was an explosive capable of penetrating Dalek casings, discovered by Daleks in an alternate timeline in the 22nd century. The secret formula for it had been stolen from the Daleks by the human resistance. Shura brought a dalekanium bomb with him to the 20th century on the mission to kill Sir Reginald Styles. He instead used it to destroy the Daleks and Ogrons who had gathered at Auderly House, thus preventing his timeline from coming to pass, but the act of detonating the bomb cost him his life. (TV: Day of the Daleks)