Upon the release of Super Smash Bros. Brawl, many Wario fans were disappointed and shocked to see that his moveset had a powerful farting attack, something that seemed unprecedented for the character to fans in the US. In Japan, Wario's association with toilet humor in promotional material dates back to Wario Land II at least. The marketing for Wario Land 4 is arguably when the gross-out humor could be considered most prominent, with the game having golden poop stickers included in its manual, and the official Japanese website going into immense detail on the size and shape of Wario's fecal matter:


Up until Brawl's release, Wario had not been associated with vulgar humor that much within actual games, and the only glimpses US audiences would've received of Wario's slobbish side in marketing would have been in animated commercials where he was animated to have saliva dripping out of his mouth (something that could be easily disregarded given that Nintendo used gross-out gags to market most of their titles in the US at the time, even for less edgy characters such as Kirby and Yoshi) and - by an extreme stretch - a subplot in WarioWare: Touched! revolving around Wario's bad oral hygiene. Following Brawl, farting would be cemented as one of Wario's signature abilities in a variety of Mario games.

The final level of Wario Land 4, Golden Passage, begins with Wario touching the frog switch, causing the entire stage to play the generic hurry up theme - if a player pauses the game before landing on the switch (or alternatively hacks the game), a unique Golden Passage stage theme can be heard.