Related Clues:

• Come unglued, with 'out'
• Unusual and unexpected event
• Rare for me, walks taken at regular intervals
• Go ballistic (with "out")
• Unusual monster
• Abnormal thing or event
• Wildly unusual
• Totally unexpected, as a storm
• "Let your ___ flag fly!"
• Wig (out)
• Completely lose it, with 'out'