Superman Rocks Beach Towel! Unfortunately "rocks" doesn't mean the same thing to Kryptonians, so many strange, delicious complications are caused by this simple mistranslation. This is why Superman never seems to use the door.  Even here, just off the towel, is an unlocked screen door which the Man of Steel completely ignores in his desire to "rocks" politely. The towel is made from 100% cotton and measures 30X60 inches.