GooKeeper is a new gameplay mode, implemented as per the game design shared by SuperSnark. This is to be taken up as a GSoC 2018 project under MovingBlocks organization.
Link to official GDD: https://forum.terasology.org/threads/gookeeper-game-concept.2099/#post-15603
The original proposal related to this project can be found on: https://docs.google.com/document/d/1f7nsJVu2HH2tjdYK1m4N74ewazA662AXpwrs0S1xldE