When a middle-aged man married for longer than 7 years gets sex two nights in a row. This is as rare as Fernando Tatis hitting two grand slams off of Chan Ho Park in the same inning.
Something that is completely superior to anything else in the same class, genre, or universe. A quote from a truly "gifted" poster on a message board describing the videogame "Goldeneye".
Non-baseball fan: Woah who's that?
Baseball fans: Oh, thats Fernando Tatis jr, the future best shortstop in the game and arguably the most attractive mlb player.