Met goes Pooops uses an organism called Methanosarcina barkeri to tell a story of how gasses are produced in the intestine. This Archaea (not bacteria!) is best known for its ability to produce methane, and is found in the intestine of humans, cows, and many other animals, working together with other bacteria to aid the digestive process.
Learn more about Methanosarcina barkeri on Wikipedia.