The duo felt it was not only critics but also fans who had grown tired of the duo, and their label who Bob felt lacked the "over-the-top enthusiasm" they bore when the duo signed with them. The duo had also grown tired of writing and playing music, and held off releasing any material for almost a year. Bob said: "We knew we had to come up with a good album or that would have been the end of it." Fruitbat of the duo said that, with "Post Historic Monsters", "we knew we had something to prove. We didn't want anybody to be allowed to dismiss us. No fucking way!" The band recorded "Post Historic Monsters" in 1993, co-producing the album between themselves and Simon Painter. Painter also engineered the album, whilst Kevin Metcalf mastered it. The duo took a much more spontaneous approach when creating the album than they had with previous albums. As such, several of the songs, which began as mistakes or lesser-projects, became fully developed songs. "The Music That Nobody Likes" had begun as a mistake, whilst "Evil" is "an experimental B-side gone haywire;" Bob said that as a result of creations such as these and the more spontaneous approach that birthed them, the album became "just so much more refreshing." Keen to "prove themselves" with "Post Historic Monsters", the album is a musical and lyrical departure from previous records by the band. According to "Deadline" magazine, it shows the band "moving into previously uncharted musical and lyrical territories," and made note of the excess of surprises on the album. The album is darker and "more fed-up" than the band's previous albums, with a directness and bitterness that contrasts with the "more overtly tongue in cheek" style of previous albums such as "101 Damnations" or "1992: The Love Album". In an interview with "Deadline" magazine, Jim Bob said "the difference between "Post Historic Monsters" and the records we have put out since "101 Damnations" is that you can listen to it without prejudice. There's none of that stuff that usually puts people off. It's like it doesn't matter that it's a Carter record. It could almost be by anyone." Like the band's previous work, "Post Historic Monsters" is a dance-rock and electronic rock album characterised by its punk rock-styled distorted guitars and chattering sequencers and electronic beats, but there are numerous exceptions to this style throughout the record, including "Being There", which features a  lounge music-styled jazz style and a piano solo, the acoustic folk of "Suicide Isn't Painless" and the ironic "mainstream schmaltz" of "Under the Thumb and Over the Moon."