Some bacteria have a very cool trick – they can form spores. Spores are made of super tough material (like keratin) and form around the bacterium encapsulating it in a kind of time machine. This spore is resistant to extreme temperatures (such as boiling water), chemical changes in the environment (e.g., radiation) and a lack of food. In fact, these unfavorable conditions can be detected by the bacteria, leading to the formation of the spore. The spore can then last for incredibly long periods of time (in the order of centuries) until the right conditions again present themselves, reactivating the bacteria.