Submersible probe droid
From Wookieepedia, the Star Wars wiki.
The Galactic Republic used submersible probe droids on waterworlds such as Manaan. One such droid was severely damaged on Manaan, and captured by the local Sith before the Republic could recover it. The Republic sent Revan to infiltrate the Sith base in Ahto City to get the data module from the damaged droid.
