The Croke Sorcerer of Tund Rokur Gepta had in his possession a biological weapon that was capable of killing living creatures and of distinguishing illusory targets from real ones. Gepta used the weapon to lure the gambler and smuggler Lando Calrissian into agreeing to a duel at the ThonBoka nebula lest Gepta unleash the power of the weapon on a spaceworthy species known as the Oswaft.