Unidentified Mustafar superweapon

A superweapon capable of releasing a deadly virus to the galaxy. By the time of the Clone Wars it had been buried on Mustafar. After learning of the existence of the weapon, General Grievous planned to use the weapon in a plan to rebel against Count Dooku. EG-07 a battle droid employed by Grievous located the weapon on Mustafar. By the time the Jedi Order had learned of Grievous's plans and tracked the weapon to Mustafar, Grievous had drilled down to the weapon and placed a battlesphere in Mustafar's atmosphere. Grievous planned to use the battlesphere's lasers to charge the weapon's long depleted power source.

In order to stop this, the Jedi dispatched Anakin Skywalker, Ahsoka Tano, Kit Fisto and Commander Cody to disrupt the sphere's three firing platforms. After the first two platforms were successfully disabled, EG-07 confronted Skywalker and Tano at the third, delaying them long enough for the platform to fire and charge the weapon. The Jedi then delpoyed Jedi Masters Mace Windu and Yoda to the surface of the planet who each made their own ways down to the weapon. Once Windu made it to the weapons control center he engaged Grievous and eventually forced him to retreat. However before Grievous retreated he activated the weapon. Luckily for the Jedi, Windu's delay of Grievous gave Yoda the time to make it to the weapon's core which he was able to destroy which prevent the weapon from firing.

Text and facts from the “Unidentified Mustafar superweapon” article on Wookieepedia, licensed under CC BY-SA 3.0. Modified for this site.