A colonoscope is a long, thin, flexible tube with a light and video camera at the tip, used by doctors to view the inside of the rectum and colon during a colonoscopy. It transmits real-time images to a monitor, allowing examination for abnormalities like polyps or inflammation, and has channels for inflating the colon with air/CO2 for better views, suction, irrigation, and passing tiny tools to take biopsies or remove growths.