Cacogens are organisms that thrive in environments with high levels of pollution or extreme conditions, such as heavy metals or toxic chemicals. They are often used in studies of ecology and environmental science to understand how life can adapt to harsh circumstances. These organisms can include certain types of bacteria, fungi, and plants that have developed unique mechanisms to survive and even flourish in contaminated habitats. Their presence can indicate the level of pollution in an area and can play a role in bioremediation, where they help to clean up polluted sites by breaking down harmful substances.