wikipedia wrote:He-Gassen (Japanese: 屁合戦) is a Japanese art scroll created during the Edo period by an unknown artist or several unknown artists.[1] The scroll depicts various scenes with one peculiar characteristic reoccurring throughout the scroll, namely that at least one character is having a bout of flatulence directed against other characters.[1] The name of the scroll roughly translates to "Farting Competition" or "Fart Battle".[1] The scroll was made with the intention to highlight the political and social changes in Japan.[1] This scroll and other similar drawings were created in response to increasing intrusion of Europeans in Japan during the Edo period.[1]
Here's some choice samples, check this article for more, or the whole scroll here