The Jells were a race of bovine creatures from the planet Jellidge. They walked upright and were locked in often pointless conflicts with their planetary neighbours on Nabrili.
The Eleventh Doctor brokered a peace between the two warring planets using a missile computer that he adapted by adding an electronic conscience (a spare part of K9's retrieved from the TARDIS) with the instruction that it was all the Nabrili's idea. (COMIC: The Peace Strike)