AMHERST, Mass. — It took a lot less than Kryptonite to fell this Man of Steel. Police in Massachusetts report that a man dressed in a Superman costume was treated for a head injury after being punched in the face last Wednesday night, apparently when he refused to get out of the way of a motorist trying to enter the driveway of a home. Amherst Detective Richard MacLean says witnesses told investigators that Superman, who was not identified but said to be of college age, had been trying to stir up trouble in the area. Police say the man was knocked to the sidewalk by the punch, suggesting, perhaps, that he had a glass jaw rather than a steel one. He was taken to a hospital for treatment of non-life-threatening injuries. The not-so-super encounter remains under investigation.