Related Clues:

• Last word of an ultimatum, perhaps
• ''Do it, or ___!''
• Where starter
• Ominous-sounding phrase
• ''Or ___!''
• See 21 Across
• Threat phrase
• ''Will there be anything __?''
• ''What ___ can go wrong?''
• "Who ---?"
• 'So what -- is new?'
• Bully's final words
• Choice introducer
• Caveat phrase
• Other than me