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.
A gender-bent Bowser, following Rule 63 of the Internet.
Bowsette has become all the rage, ever since someoneposted 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 long period to all who don't get it. This eventually causes it to not be funny.
While our lifespan is the number of years we will live, our healthspan is the number of healthy years we will have and our sexspan is is the number of years we will continue to be healthy enough to continue having an active sex life.
A lighthearted reaction upon receiving disappointing news of some sort. Usually something that isn't a particularly a big deal, esp. when it primarily affects someone else - sort of a mild schadenfreude. Sometimes doubled or tripled, and possibly said in a sing-songy voice for added comedic effect to imitate a muted trumpet, which is how the meme originated.