The long-awaited season 4 of Rick and Morty is almost here, and the trailer has confirmed several returning characters - including Messrs Meeseeks and Poopybutthole.

Premiering in 2013, Rick and Morty became a monster hit for Cartoon Network's Adult Swim block. Originally starting out as a crude parody of Back To The Future (which Justin Roiland created as a joke to see how quickly he could get a Cease and Desist order from Universal Pictures) the show about a dimension-traveling mad scientist and his dim-witted grandson evolved into a spirited science-fiction epic in its own right. Recently Rick and Morty was confirmed to be part of a selection of shows acquired by HBO Max, but the first three seasons and new episodes from the upcoming season 4 will continue to be available through Hulu in the immediate future.

Related: Why Rick & Morty Season 4 Is So Much Shorter

Apart from Rick and Morty themselves, fans can expect to see the rest of the Smith Family return for season 4. Yet there are even more popular characters from earlier seasons coming back, whose presence in the new season was confirmed by the first trailer. Here's a rundown of every returning character confirmed for Rick and Morty season 4.

The Meeseeks

Rick and Morty Season 4 Meeseeks

The Meeseeks, all of whom go by the name Mr. Meeseeks, are among the most popular guest characters in Rick and Morty. First appearing in the season 1 episode "Meeseeks and Destroy," the Meeseeks are summoned into being to accomplish a single task before they cease existing. While they are incredibly loyal and friendly, they become erratic the longer that they exist and will resort to killing their creator if given an impossible request. One scene in the trailer confirms that Rick and Morty season 4 will see the return of the Meeseeks - on the rampage once again.

Mr. Poopybutthole

Mr. Poopy Butthole teaches a class in Rick and Morty.

First appearing in the season 2 episode "Total Rickall," Mr. Poopybutthole was a long-time friend of the Smith family and one of the few people Rick Sanchez trusted implicitly. Mr. Poopybutthole's appearances on the show since then have been limited to fourth-wall breaking cameos at the end of season 2 and season 3, where he told viewers to be patient waiting for the upcoming seasons of Rick and Morty, as well as a video released online which revealed something of his background. The season 4 trailer suggests he'll be taking a more active role in at least one episode, with Mr. Poopybutthole depicted teaching a college class and fighting his suddenly enraged students.

Revolio Clockberg Jr.

Rick and Morty Season 4 Meeseeks Fights Morty With Gearhead Revolio Clockberg Jr

More commonly known as Gearhead, Revolio Clockberg Jr. is one of Rick and Morty's strangest side characters, as well as one of the rare reoccurring characters who has made at least one speaking appearance each season. An old friend of Rick's, Clockberg was last seen in the season 3 episode "Vindicators 3: The Return of Worldender," where he was dismembered while fleeing a monster attack in the post-credits stinger. It appears that he was reassembled, however, as he can be seen in the season 4 trailer, sitting in the back of Rick's flying saucer, as Morty (who is wearing a Nazi military uniform for some reason) struggles with a Meeseeks.

More: What To Expect From Rick & Morty Season 4