“Lady Abundance of Jewels” married a mortal man, but warned him
not to look upon her as she gave birth to their child. (Similar
to the story of Melusine.) Her husband could not stay away, and
peaked into her hut made of Cormorant feathers (as all birds are
sacred to her) where he saw her in her true form, that of a
serpent/water dragon. Toyota-Mahime was so upset, she retreated
back to the ocean, with the child, and forever closed the doorway
that joined her realm to the realm of mortals.
JAPANESE MYTHOLOGY & FOLKLORE 