WariMari

WariMari is the slash ship between Wario and Mario from the Super Mario fandom.

Canon
According to both the 1993 Nintendo Character Guide and Mario vs. Wario, the two were originally childhood friends who would play together. Due to Mario not being considerate of Wario's well-being during their playdates, they eventually became rivals instead. Wario continues to hold a grudge towards Mario during their adulthoods.

The duo are first depicted in Super Mario Land 2: 6 Golden Coins. While Mario was saving Princess Daisy, Wario got to work. He casted a spell on Mario Land to convince the inhabitants Wario was the true owner and Mario was the enemy. Wario proceeds to steal Mario's castle. Arriving home, Mario collects the six Golden Coins to be allowed entry into 'Wario Castle' and defeats Wario. After Wario flees, 'Wario Land' is restored back to Mario Land.

In games such as Mario Tennis and Mario Party, their rivalry is still fairly aggressive. The intro of the first Mario Tennis games has Mario and Wario glaring and insulting each other to the point where bystanders show concern. Mario Power Tennis has Wario join in with Waluigi to graffiti posters of Luigi and Mario, which they almost get arrested for. The duo then team up with Bowser to attack the Mario Brothers with bombs. They are promptly defeated. In both the new intro and beginning of Mario Tennis Aces ' story mode, Wario and Waluigi become possessed by Lucien. They attempt to have Mario join them by giving Lucien to him, but Luigi takes the racket instead. Mario and Wario's team names in the Mario Party series are 'Alter Egos,' 'Big Sarrios,' and 'Foe Bros.'

The Nintendo Power series, Mario vs. Wario is about Wario getting revenge on Mario. In the first issue, Wario invites Mario over so he'll eventually fall for at least one of his many traps. Unintentionally, Mario gets past all of them, leaving Wario to cry. Mario attempts to cheer him up with a game of Cowboys, upsetting Wario even more. During the second one, both men notice Princess Peach's interest in a Samus doll. After they find out it was already sold, they both buy a jack-in-the-box to swap with the other's gift. This upsets Peach, causing Luigi to reveal he was the one who bought the doll.

Fanon
While the ship is fairly underground in the west, the pairing is more commonly found on Japanese websites such as Pixiv. The canon ex-friendship and rivalry has some fans prefer the pairing. Furthermore, their relationship ending with romance falls into the enemies to lovers trope.

One notable fan portrayal of the ship can be found in the fan game, Wario Date. The goal of the game is to romance several characters into getting a large sum of money. However, the player can settle down with one character if they wish. Here, if Wario decides to join Mario in his adventure and asks if he'd be okay to go on a date, Mario will agree without a second thought. During their picnic date, if Wario asks, Mario may begin to vent about how he feels seperated from his friends, especially Peach and his brother. Wario will then have the choice to comfort him and settle down with him or mock him and leave. The former results in them kissing. It is worth noting the game also has the option of killing Mario if the player selects the Bowser route.

PIXIV
マリワリ on Pixiv

ワリマリ on Pixiv

Trivia

 * Wario's name is a combination of 'Warui' (Bad) and Mario. Thus, his name is 'Bad Mario.'
 * Mario is able to dress up as Wario in both Paper Mario: the Thousand Year Door and Super Mario Odyssey.