Related Clues:

• Gnaw toothlessly
• Adhesive
• Sign of foreboding
• Tooth support
• Dark clouds on the horizon, say
• Portentous event
• Dark clouds, say
• Word with chewing or bubble
• Evil sign
• Hooting owl, maybe
• *Eclipse ... black cat ... future
• Warning
• Extra, e.g.
• Sticky substance
• Writing on the wall