The Rebis (from the Latin res bina, meaning dual or double matter) is the end product of the alchemical magnum opus or great work.
After one has gone through the stages of putrefaction and purification, separating opposing qualities, those qualities are united once more in what is sometimes described as the divine hermaphrodite, a reconciliation of spirit and matter, a being of both male and female qualities as indicated by the male and female head within a single body. The sun and moon correspond to the female halves, just as the Red King and White Queen are similarly associated.
The Rebis image appeared in the work Azoth of the Philosophers by Basil Valentine in 1613.