Possible Clues:

• Theoretical lowest temperature
• -273.15 Celsius
• You can't get colder than this
• *Temperature at which you can’t get any more chill?
• Theoretical temperature at which molecular activity ceases
• Theoretically, the lowest of the low in the terribly cold state
• Coldest temperature
• -273.15°C
• Lowest theoretical temperature
• Very cold temperature