Crawl-carrier

An espionage and infiltration droid that was used during the Clone Wars and developed by the Confederacy of Independent Systems. They were squat rectangular in shape with eight legs. They could be fitted with a variety of equipment; from acid, personnel explosives, electrical disruptors and even smaller droids. Their small size allowed them to reach locations that organic beings and larger droids could not reach. Once reaching their target they would use the weapons they were outfitted with to cause havoc within enemy positions. This made them a perfect tool for the Separatists in attempts at terrorism.

The primary production facility was located on the planet Dagro which was destroyed by Obi-wan Kenobi and Anakin Skywalker one years after the Battle of Geonosis.

Source

 * Star Wars Insider Magazine