The word "Bazinga" was first used in the season 2 season finale, "The Monopolar Expedition" and last in Season 8 episode 15, "The Comic Book Store Regeneration". (Seasons 6 and 7 are devoid of it.) By this time Sheldon has developed a mediocre sense of humor and instead uses a peculiar form of laughter instead – both literally and sarcastically. Jim Parsons has been quoted as crediting former The Big Bang Theory writer Stephen Engel as the one who came up with the word Bazinga for Sheldon's catchphrase. Furthermore, Bazinga implies swag.