63. Metagram, a riddle in which the change of the initial letter produces a series of words of different meanings; from meta, implying change, and gramma, a letter. Thus:-

I cover your head,; change my head, and I set you to sleep; change it again and again, and with every change comes a new idea.--Cap, Nap, Gap, Sap, Hap, Map, Lap, Pap, Rap, Rap, Tap. This kind of riddle is also known as word-capping.