Defilak's Submarine was an underwater craft designed in the shape of a Takea Shark and constructed by Defilak. He initially designed it for a Po-Matoran in order to search for rocks without having to swim; however, the Matoran eventually refused to ride in it and the craft was hidden. When it was decided in the Matoran Council Chamber that an expedition was to be sent to explore the uncharted areas around Mahri Nui, Defilak suggested they should use this vehicle.
Defilak, Gar, Idris and Sarda piloted the craft for a short while, however they were eventually attacked by a group of Takea sharks led by Pridak. It was badly damaged and eventually sank to the bottom of the sea.