Intussusception in adults lacks specific symptoms and is often diagnosed emergently when they present with obstruction. Though intussusception certainly varies in size and location, the increased likelihood of ischemia or obstruction make large intussusceptions very rare in the literature. A patient admitted to our facility for small bowel obstruction was found to have extensive intussusception from the right lower quadrant to the splenic flexure, where a lead point was identified. Histopathology revealed multiple satellite lesions surrounding the lead point tumor, which was found to be invasive mucinous adenocarcinoma of the ileocecal valve. While malignancy is found in 60% of lead point identifiable adult intussusceptions, a malignancy is always found in the case of an exceptionally large intussusception.