Thought Bomb
this weapon, first devised and last used by Lord Kaan and the Brotherhood of Darkness, was essentially a seething collection of Dark Side energies. The ancient Sith discovered that the Dark Side of the Force could be extracted and mentally bound into an explosive sphere. When set off, in the final struggle of the Battle of Ruusan, the thought bomb obliterated the physical bodies of both the Sith and the Jedi, trapping their spirits in an unbreakable forcefield for all eternity. The natives of Ruusan believed that their imprisonment would last until another Force user came and disrupted the natural order of the Valley.