Ancient people often associated greed with the sea, because no one could measure water. On tropical beaches, there is a type of crab (scopimera globosa), only the size of a carp's eye, that often rolls sand into balls like dung beetles. It is said that they are descendants of a grieving old man who wanted to fill the sea to take revenge on the sea king. There are two stories related to this:

Once, a Chinese king, while strolling on the beach, witnessed a scene: A female crab was ill, and a male crab cared for her, but when she recovered, she left with another male. The king was furious, so he ordered that any man willing to kill wife would be rewarded. While many men did so, one young husband hesitated when he heard his child crying. He begged the king for forgiveness, but the king rewarded him with half the kingdom.

An old man in middle-age Vietnam was given a gem by a male snake (similar to the story above), which allowed him to understand the language of animals. This gem helped the old man save a goose family from being slaughtered, so the geese gave him another gem, which allowed him to go underwater without getting wet. He immediately went into the sea to cause the dragon palace to tilt. The sea king then tricked the old man's wife, promising to marry him if she stole the gems. She agreed and died in the sea. The old man, filled with resentment, carried sand to try and fill the sea. After the old man died, the heavenly king took pity on him and transformed him into a crab.