Odysseus departed Circe island with his crew refreshed, but with knowledge of the great challenges to come.
The first obstacle was the Sirens. They were beutiful creatures with voices so powerful the sound could draw boats to there doom, crashing into the rocks. Then the Sirens would feast on the dead mens bodies. Odysseus instructed that his crew to fill their ears with bees wax and tie him to the ships mast, so that he could sfelfy listen to the calls of death.
The ship safely sailed by due to Odysseus's plan, and no lives were lost.
Odysseus, able to hear the creatures, struggled with all his might against the ropes but they heald and once the sirens song was gone Odysseus calmed down.
Next Odysseus had to choose the lesser of two evils. There were two monsters in his path and he must pass one. If the chose the whirpool monster Charybdis, then his entire ship would sink.
He passed by Charybdis into the jaws of the second monster, the six headed Sylla.