Why Adult Swim's 'Rick and Morty' Is Millennials' Favorite TV Show

Pickle Rick. Get Schwifty. Wubba lubba dub dub. Those phrases may not strike a chord with you. But, for TV viewers of a certain age (adults between the ages of 18 and 34, for instance), they should be instantly recognizable from the Cartoon Network/Adult Swim animated series, Rick and Morty: millennials’ favorite TV comedy.

Currently in its third season since debuting in 2013, the show is part intergalactic adventure, part family comedy, led by a brilliant but caustic (and alcoholic) scientist, Rick, and his relatively average teen grandson, Morty. Stacked deep with pop culture references and absurdist nihilism, Rick and Morty doesn’t seem like a safe bet for broad appeal on it surface.

But, overall viewership for the current season is up 81% over the previous season, and the series is the number one comedy on TV so far this year in the coveted demographics of adults 18-24 and adults 18-34, based on Nielsen ratings that track live viewership plus streaming and on-demand viewing over an initial week-long period. By that measurement, Rick and Morty is outpacing award-winning broadcast TV shows like CBS’ The Big Bang Theory and ABC’s Modern Family with younger viewers this year.

Christina Miller, the president of the Time Warner-owned Cartoon Network and Adult Swim, told Fortune that Rick and Morty goes beyond just appealing to millennials, though. Based on recent ratings, more than 2.5 million people overall are likely to tune in for the current season’s finale, which premieres this Sunday night at 11:30 pm ET. Those are especially impressive results for an animated show that’s definitely aimed at adults (most episodes feature adult language and animated violence), much less one that airs so late on Sunday nights. Those numbers also suggest that people of all ages are watching the show, and Miller thinks the audience will only grow more.

“I do think more people will come to it,” Miller said. “But, more importantly, they’re staying with it, and that’s been the difference-maker.”

Get Data Sheet, Fortune’s technology newsletter.

Indeed, Rick and Morty’s early fans exercised no small amount of patience over the nearly two-year period that lapsed between the end of the show’s second season and the current season’s official return over the summer. In the world of “Peak TV” and countless entertainment options, two years is a long time to stay excited and engaged with a TV show.

And, yet, instead of hurting the show, though, Rick and Morty returned from its long absence with a stronger viewership than ever. First, the show briefly returned to TV in an April Fools Day stunt, when Adult Swim surprised fans by streaming the first episode of Season 3 online in a constant loop for four hours on April 1. The streams pulled in 3 million unique visitors, while a similar livestream hosted on Facebook got 8.7 million video views. (The show’s social media following is also very strong and active, with more than 2.8 million followers on Facebook, plus more than 1 million on Twitter and 1.6 million on Instagram.)