We present a unique case of an inverted diverticulum mimicking a large adenomatous pedunculated polyp. Inverted colonic diverticula (ICD) are typically a few millimeters in size and may resemble a polyp. Our finding was unusual based on its size, location, and appearance. Incorrect management of ICD can lead to serious complications, therefore, endoscopists should be aware of this occurrence and approach suspicious lesions with caution.