Related Clues:

• Curiosity
• Quirk
• Blue moon, e.g.
• Hen's tooth, e.g.
• Marvel
• Three-legged calf, e.g.
• Eccentricity
• Peculiarity
• One for the books
• Three-legged calf, for one
• Rare find
• Quirkiness
• One for the record books
• Exception to the rule
• Hole in one, e.g.