A colonoscope is a thin (10mm) tube that contains a lighted camera.  It also has channels in it so that different instruments (like small forceps to biopsy things or snares to remove polyps) can be passed into your colon during the exam.  This makes the colonoscope a tool that helps us both detect polyps and removed polyps during the same exam.  It is used by gastroenterologists, like me, to treat bleeding in the colon, remove polyps, detect colon cancer and remove foreign objects (yah you read that right).