The game, New Super Mario Bros. U Deluxe, released a new item called a Super Crown. The item allows Toadette to turn into a new version of herself called Peachette. When the internet saw this they made their own version involving Bowser.
Bowsette has become all the rage, ever since someone posted a Twitter comic of him donning Princess Toadstool's Super Crown from the new Super Mario Bros U Deluxe, and turning into a rival for Mario's affections.
Where the geezer tells the joke, laughing at the joke and then has to explain it for a longperiod to all who don't get it. This eventually causes it to not be funny.
Guy 1: Did you not get the joke?
Guy 2: Nah I didn't, but don't start that Bowkett humour again !