kicker
n. countablen. a surprising fact or extra detail that makes a situation more interesting or difficult. It is often the final point in a story that changes how you feel about it.
n. an unexpected or surprising remark, circumstance, or detail that concludes a sequence of events. Often used to introduce a final complication or a 'twist' in a narrative.
The car was cheap, but the kicker was the expensive insurance.
He offered me a great salary, but here is the kicker: I have to move to another country next week.
The legal team thought they had won the case on a technicality, but the real kicker came when the prosecution produced a previously unknown witness at the final hour.
From kick + -er.
The southern-U.S. sense referring to a person derives from shitkicker, referring to a cowboy with boots used to kick away cow manure.
Often preceded by the definite article in the phrase 'the kicker' or 'here is the kicker'.