It is not the anus that prolapses specifically, but the rectum. When a prolapse occurs, the rectum essentially everts, turning inside out and protruding from the anal opening. It will appear as a pink or red tubular structure. If a prolapse has just occurred, the tissue may still appear moist and healthy. In chronic prolapses, the tissue may become more irritated, have litter or other foreign material stuck to it, or have a crusty and oozing appearance.