This defective R2 unit was an astromech droid in service with the Galactic Empire during the Galactic Civil War.
This R2-series astromech droid was present on the Executor a short time before the Battle of Hoth. Unknown to Darth Vader, this droid was actually a spy for Emperor Palpatine. When Palpatine discovered one of Vader's secret apprentices, Tao, he attempted to transmit a message to Vader through the droid's holoprojector.
The droid initially began to malfunction, and it crashed into Vader as he was standing on the bridge. Vader ordered one of his officers to dispose of the droid, but before the Imperial could obey, Palpatine's voice and image emanated from the droid. Vader was shocked by Palpatine's appearance, especially when Palpatine revealed that he knew about Tao. Two Royal Guardsmen presented Tao before Vader, and Palpatine's image ordered his apprentice to dispose of the boy. Vader obeyed, and Palpatine, satisfied, turned off the hologram. The R2 unit, puzzled over being taken over, returned to its duties.
This unidentified droid only appears in the story Perfect Evil, which spanned issues Black and Silver of Star Wars Manga. Originally published in Japan, those stories were considered to be of "fuzzy" continuity by Lucasfilm. Since then, they have been republished in English in the United Kingdom under Infinities label, which established the material in them as non-canonical. The planet Shumari has been later referenced in The Essential Atlas, which included the Shumari system in its appendix. However, according to Jason Fry, "its inclusion shouldn't be taken as a statement of canonicity for anything except the geography."