The legend of ancient elixir of life?

Introduce some foreign stories: the story of forgotten one, a Sumerian in the west. He got the elixir of life through hardships, but at the end of the story, the fairy medicine was eaten by the snake, and the snake could shed its skin and be reborn.

There is also the story of the Indian gods stirring up the milk sea and the fairy water, making them immortal.

In Egypt, immortality is a magic book belonging to Thoth. A prince got eternal life after getting it, but the angry God deprived him of this right, killed his wife and children, and finally the prince committed suicide.

The goddess Eden in northern Europe has a youthful apple, which is also an elixir of life. When the immortal is old, he can regain his youth by eating an apple.