Droidekas, also known as Destroyer Droids, were a type of droid used by Confederacy of Independent Systems during the Clone Wars After Clone Order 66 and The Great Jedi Purge, the whole battle droid army was given a shutdown command.
Droidekas were dangerous and deadly, designed to exterminate their adversaries with extreme prejudice. They could transform their shape by curling into a ball and moving across a surface, or stand on three legs and utilize a shield generator while firing at a target.
During the Clone Wars, these types of Droids were deadly killers and a formidable foe. Most of them were wiped out when Emperor Palpatine executed Order 66, but some of them along with General Kalani went to the planet of Agamar.