Possible Clues:

• Warn Henry in a whale of a way
• Creature known as the "unicorn of the sea"
• Water initially flowed up - almost 50% whale appearing
• Marine creature managed to back onto itself almost
• Warn Hal there's a whale here
• This might warn Henry of a sea monster.
• Is that the hidden way to warn Henry there's a tusk there
• An Arctic whale
• Toothed whale from the Arctic
• Hurried up with most of a whale for a whale