Namazu/ナマズ is the Japanese word for catfish.
So,大鯰/Onamazu means “Giant Catfish”.
Guess what this big guy spends his time doing… Swimming around? Eating?
This is a Japanese mythological story.
Onamazu is said to live in the mud under Japan and he is restrained by the god Kashima.
When Kashima let’s his guard down (or let’s go of the rock that pushes Onamazu down) Onamazu get’s up to mischief.
The catfish thrashes around and that’s where earthquakes come from, kids.
This mythology is still alluded to today on earthquake signs in the street:
Researchers actually studied catfish for 16 years to see if there was any correlation with their behaviour and earthquake occurrences.
No, I’m not joking.
Check out the 1992 article here.