A guy who defeated the evil Dark Lord from Super City Central. And now he's officially a hero! You may or may not know him from his youtube channel called "Super Mario Bros The Channel". (cuz SMBTC is an acronym for Super Mario Bros The Channel).
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.