What is the author's style in The Autobiography of Mark Twain by Mark Twain?

Twain was known as a humorist and demonstrated a playful quality in most of his writings. This is evident throughout the book, in which he uses humorous phrases to describe situations, such as when wasps are crawling up the leg of a boy so stricken with shyness by some girls in the room that he cannot move. Twain describes the wasps as "prospecting around," and says that "one group of excursionists after another climbed up Jim's legs and resented even the slightest wince or squirm that he indulged himself with in his misery." By employing interesting words like "excursionists" in obviously unconventional ways, Twain elicits a laugh from his readers.