A Trade Federation C-9979 landing craft was assigned a masculine-programmed B1-series battle droid sentry, designated 8557. Like all B1 battle droids, 8557 possessed black sensors. An E-5 blaster rifle was the weapon carried by 8557. During 32 BBY, Obi-Wan Kenobi, a Jedi Padawan, infiltrated 8557's landing craft and sabotaged the atmospheric turbine engines, forcing the vessel to land on Naboo. 8557 was then ordered by another battle droid to investigate the Turbine Control room malfunction.
Kenobi then encountered 8557, and used his lightsaber to destroy the droid sentry before continuing further into the ship.
In the 2001 video game Star Wars: Obi-Wan, 8557 appears in the Stowaway mission after Kenobi (controlled by the player) has disabled the engines. Destroying 8557 is not required, however, this article operates under the assumption that the player eliminates every battle droid. Players have the option to use a Force push instead of the lightsaber to defeat 8557. The strategy guide mentioned the droid, instructing players to proceed through the door that 8557 opened.