Whimsicore

Whimsicore is a term coined by Rectus Abdominus as a way to describe their music and overall lyrical theme throughout all of their songs. They have also referred to their music as emojicore, tardcore or sillycore as interchangeable terms with whimsicore. 
According to Jade Vitriol, Rectus' main inspiration for much of their music were bands such as Tenacious D, Steel Panther, The Lonely Island, and notably, Cockpunch. Jade claimed that this band was a primary influence on Rectus Abdominus, stating "we could form a band" following him listening to the record "birth of cool". Much of their current music revolves around internet humor of the time that the internet happened to have popular, or general Generation Z humor.
Shitcore was the first genre term for the band, with the band calling themselves emojicore between 2017-2020, then calling themselves sillycore from 2021-2023. Whimsicore would be coined around 2023, following the release of Palace of the Porcelain Throne. 
Jeff The Epic claims that the term comes from the fact that the music is "full of whimsy". The differentiation between comedy rock and whimsicore according to Jeff comes from the stylistic diversity of Rectus Abdominus, specifically that "comedy rock is...rock, and whimsicore can be anything".
All of their albums have at least one aspect of whimsicore, or general comedy rock, starting all the way back from Fully Erect. Most of their songs have to do with poop.