Related Clues:

• 'It's a mystery'
• [   ]
• 'It's anybody's guess'
• It's a mystery how not a single snout can sound like this
• 'Your guess is as good as mine'
• "No one knows"
• Question suggesting 'Beats me!'
• 'No one knows'
• "Your guess is as good as mine"
• "There's no way to know, is there?"