Isaac Asimov and Woodlice
When he was a young child, Isaac's mother was startled by the strange expression on his face and asked him what was wrong. He was unable to reply so she became alarmed by this apparent affliction. Isaac, in an effort to calm his mother spat out a mouthful of woodlice.
When asked why he had done such a thing, he replied that he had thought that they would probably tickle his tongue as they walked about inside his mouth. Apparently they did tickle - although his mother did not appreciate this turn of scientific curiosity.