In Japanese mythology, the Namazu (鯰) or Ōnamazu (大鯰) is a giant underground catfish who causes earthquakes.
The creature lives under the islands of Japan and is guarded by the god Takemikazuchi enshrined at Kashima, who restrains the catfish with a stone. When the Kashima-god lets his guard fall, Namazu thrashes about, causing violent earthquakes.