The meme refers to the old adage "C lets you shoot yourself on the foot. C++ lets you shoot both feet and gives you a shotgun to do it" - referring to the how C allows you to perform memory-unsafe operations (causing corruption, or worse, security vulnerabilities), and C++'s complexity, potentially obscuring such unsafetyness.
Rust's memory safety tries to save you from doing (un)intentional bad stuff, by giving you compile-time errors. It's also the bane of everyone so used to C/++'s ability to just pass around and modify whatever memory they want.
Oh wow thanks, TIL. I was a kid in the 90s, and always taught and read "there's many guesses, but the most likely theory is a massive impact causing global changes". And only today I learnt that it was a relatively new theory at the time, and the crater wasn't even identified until the early 90s!