They were produced in secret factories, and the Galactic Republic first learned of their existence when they were deployed against the Republic some time between the First Battle of Geonosis and 21.5 BBY. They were spherical in design, and they were capable of maneuvering down sinkholes on Utapau.
- Shatterpoint (First appearance)
- CIS Shadowfeed Dispatch 15:3:21 Edition
- Star Wars: Episode III Revenge of the Sith novelization
- Star Wars: Episode III Revenge of the Sith unabridged audiobook