Related Clues:

• It may do a number on your slumber
• Warning bell
• Informal greeting
• Eye opener, of a sort
• Chili-hotness measure
• Perturbation
• Clock partner
• Snooze, for one
• It might scream after being tripped
• Eyeopener?
• Warning signal
• 40-Across producer?
• Source of a wake-up call
• Firebox feature
• Trepidation