When Re was in the underworld, he merged with Osiris, the god of the dead, and through it became the god of the dead as well. The union of the gods Re and Osiris (in the guise of a ram-headed mummy which wears the sun’s disk between its horizontal, corkscrew horns).
Detail of a wall painting from the Tomb of Queen Nefertari (QV66). New Kingdom, 19th Dynasty, ca. 1292-1189 BC. Valley of the Queens, West Thebes.