Tarnation is an old American folk exclamation formed from tarnal and damnation, recorded in the United States since the late 1700s and long associated with rural Southern and Western speech. Minced to avoid outright swearing, it became a stock line for flustered cowboys, farmers and cartoon characters in Westerns and animation. Online, the phrase was shortened into a standalone reaction clip, shared on soundboards and in meme edits whenever a creator needed an instantly readable, old fashioned way to say they were completely baffled by something.