Demeter and Persephone
Greek mythology
The Mother who loses her daughter to the underworld and grieves so deeply that the world turns to winter. Persephone's descent IS the daughter's individuation: separation from the Mother that the Mother experiences as death.
Individuation hurts the Mother. The daughter's growth is the Mother's grief. Both are necessary.
The pattern underneath: The Great Mother. The biggest version of the Mother: nature itself as a force that creates and destroys.