Kar-Charratan

Kar-Charratans were aquatic life forms who lived on Kar-Charrat that survived in liquid form, usually in water. They had the capability to inhabit life forms containing water, and were able to attack any organisms. They even talked through raindrops.

Some were captured by Chief Librarian Elgin and placed inside the wetworks facility, where they were used to download data. (TV:  The Genocide Machine)