Based on the provided information, it seems that there is no text available for extracting relevant keywords or information related to the topic of what freezes after being heated up. However, based on the given riddle, here is a list of pertinent keywords related to the topic: 1. Freezing point 2. Melting and freezing 3. Phase change 4. Substances freezing and melting Please note that without additional context or specific information, it is difficult to provide a comprehensive and relevant list.