Possible Clues:

• A rock transported by glacial action
• Wandering rodent getting in damaged rice
• Unpredictable boy snaring rodent
• Unreliable quote about a bishop returning
• Volatile racer -- tricky to hold it back
• Irregular or unpredictable
• Volatile, unpredictable
• Liable to sudden changes
• All over the map
• Idle maybe, clutching rodent? Most unreliable