Rainmaker

Rainmaker is a Ranked Battle mode in Splatoon that was announced in the Splatoon Direct on May 7, 2015 and will be added in a future update. Nothing is known about it other than that it will somehow use the weapon shown above, which appears to be a metallic fish with a nozzle in its mouth, known in Japan as a Shachihoko.

Recently, it was leaked how this mode will work.