The Rick and Morty comic is a continuation of the adventures of the popular Adult Swim show, and when Rick is trapped in a Groundhog Day time loop paradox, the reason for him being so smart is revealed!
Living, dying, and repeating the same day in Rick and Morty #49, by Kyle Starks and Marc Ellerby, this issue sees Rick and his grandson, Morty, crash land on a far-off planet where they inexplicably find the skeletal remains of some other version of themselves. Soon caught in a repeating loop after Rick awakens over and over just before the crash, neither Rick nor the oblivious Morty can figure out what’s going on with any degree of accuracy.
Once realizing they’re stuck in a “Groundhog Day” scenario — a reference to the classic Bill Murray time loop movie of the same name — Rick gets overly excited at the prospect of being able to repeat the same day without losing any actual time. And as the same day keeps resetting, Rick begins to take advantage of their predicament, ignoring Morty and his attempts at freeing them from their ever-looping lives.
Exploiting the time loop to the best of his abilities, Rick is seen binging a show he doesn’t particularly like, playing video games, getting a massage by a group of aliens, cheating at galactic poker, teaching alien blobs the “Thong Song”, and more, but it’s the handful of days where Rick Sanchez quietly sits in a library reading as many books as he can before the day resets that shows fans how some of his super smarts came to be. Going on to eventually get sick of all the repetition and learning, Rick exclaims, “I’ve done everything anyone can do in a day, Morty,” and, “I’ve experienced every experience,” Rick confirms that other than the fun shenanigans he's been involved in, he’s also studied and learned every single thing he can until he finally ran out of ideas!
An extremely smart character well before this particular comic book adventure, Rick pulling a Bill Murray and mimicking his movie character’s journey in an infinite time loop is a perfect way to explain how Rick has amassed such a vast wealth of knowledge. And judging by the way Rick reacts to the fact that he’s done everything and anything he possibly can, it’s safe to assume that after this issue is over, he’s officially become the most intelligent he’s ever been and will ever be.
So while this single instance isn’t the sole reason for Rick being one of the smartest people in the multiverse, it still shows how he’s acquired at least some of his infinite brilliance. Rick and Morty are always up to something wacky, but getting to relive Groundhog Day is probably one of the best and most inventive situations they’ve gotten themselves into yet.