You are correct! Methanogens are organisms that are poisoned by oxygen.

Here's why:

* Methanogens are anaerobic: This means they thrive in environments completely devoid of oxygen.

* Oxygen is toxic to them: Oxygen molecules interfere with their metabolic processes, specifically the enzymes involved in methane production.

* They live in extreme environments: Methanogens are found in places like swamps, marshes, the guts of animals (like cows!), and even deep within the Earth where oxygen is scarce.

Let me know if you'd like to know more about methanogens!