We have come across a series of variations on our cadaver during routine dissection of the abdominal viscera. The amount and extent of the variations were unexpected in one cadaver, and they were followed one after another as listed: a peritoneal cyst formed by the parietal peritoneum that was stuck to the anterior surface of the right kidney, intraperitoneal duodenum, intraperitoneal ascending colon, partially constricted transverse colon, and several peritoneal strings running in between the various parts of the visceral peritoneum and the parietal peritoneum covering the abdominal wall, unusual location and size of the root of mesentery, and agenesis of the vermiform appendix. Our cadaver's medical history has not shown any surgery; it never showed any scars on the abdominal wall that might have indicated surgical operations. Peritoneal variations and agenesis of vermiform appendix are of great importance during diagnostic monitoring as well as surgical interventions. Extensive peritoneal variations in one patient may cause some extremely critical complications during the peritoneal dialysis, as well as during the laparoscopic approaches. We present these multiple and complex variations in one cadaver with respect to serious clinical complications that may come out because of ignorance of such cases.