Possible Clues:

• Peril with Charybdis
• A dangerous choice for mythological sailors
• Female sea monster in Greek myth, lived opposite whirlpool Charybdis
• Lake covered by grotesque scaly monster
• Six-headed monster (opposite Charybdis)
• Rounding cape, friend's repelled sea monster
• Friend's going north to catch cold sea monster
• Mythical sea monster
• Classically either the rock or the hard place
• The danger to shipping did not turn on your side at last