Carrying Cerberus from Hades to the upper world.
The statue of Serapis in the Serapeum of Alexandria was of purely Greek type and workmanship - a Hades or Pluto enthroned with a basket or corn measure on his head, a sceptre in his hand, Cerberus at his feet, and (apparently) a serpent.
The third and twelfth labours may be solar, the horned hind representing the moon, and the carrying of Cerberus to the upper world an eclipse, while the last episode of the hero's tragedy is possibly a complete solar myth developed at Trachis.
For my own part, I was never so effectually deterred from frequenting a man's house, by any kind of Cerberus whatever, as by the parade one made about dining me, which I took to be a very polite and roundabout hint never to trouble him so again.
One of the tasks imposed upon Heracles was to fetch Cerberus from below to the upper world, a favourite subject of ancient vase-paintings.