"What in tarnation" is a phrase used as an exclamation of surprise or anger. It is considered a mild oath that comes from the time of the American Old West because it is associated with a cartoon character set in the Old West, Yosemite Sam; however, the term is actually older than that. The expression "what in tarnation" dates back to the 1700s and is derived from the mildly offensive word, "darnation". "Darnation" was a word used in place of "damnation" so as not to upset polite company. The word "tarnation" is also influenced by the word "tarnal," another euphemism that was a substitute for the word "eternal," meaning God. The phrase is an American idiom and is still used today in some parts of the United States.