The medical term for the condition of passing feces containing fat is steatorrhea.

If an animal's feces smells like a dead animal, the animal is probably sick. There is most likely a problem with their digestive track.

Feces containing excess water is called diarrhea. One of the most common causes of diarrhea is an infection of the intestines.

Because it contains undigested food, mucus, dead body tissue and toxins

Feces is correct in America. Faeces is correct in International English.