Remember the Incredible Hulk TV show? A failed experiment exposes mild-mannered Bruce Banner to gamma radiation, causing him to become a brainless monster. Every episode some poor sap would punch Bruce in the nose only to find himself confronted by Lou Ferrigno in green body paint.
But this is a serious program, so let's get serious. Just what is gamma radiation, and can it really turn you into the Hulk?
Answer to the second question: no. As for what gamma radiation is, now we're talking science. Gamma radiation is one of the many kinds of electromagnetic radiation, or light, in the universe. In fact, the only difference between regular light and gamma radiation is that gamma rays exist on the highest end of the electromagnetic spectrum, meaning that they are very energetic, and we can't see them.
One source of gamma radiation is a nuclear reactor. When atoms are split they release gamma rays along with other kinds of nuclear radiation. Under normal circumstances nuclear radiation is contained in the reactor. But as you might imagine, exposure to intense gamma radiation resulting from a nuclear meltdown would be deadly.
A more benign and exotic source is outer space. Exploding stars called supernovas radiate gamma rays and other kinds of light. These extraterrestrial gamma rays travel through the universe and constantly bombard Earth, passing through everything including our bodies.
For the most part these gamma rays are harmless, but just as overexposure to X-rays is harmful, prolonged exposure to naturally occurring gamma rays may cause skin inflammation and even damage cells deeper in the body.
So although gamma radiation won't turn you into a green monster, it's best avoided in any case.