The most bizarre and spooky song on Paper Mâché Dream Balloon is “Trapdoor” — a fast-paced, Krautrock inspired piece with repetitive lyrics. The lyrics describe a trapdoor, but keep what’s behind it vague by saying that everyone already knows what’s there, and that we all collectively hide it. Perhaps the band is commenting on our desire to hide our darkest secrets and fears behind our own trapdoors, or more literally that there is some mythical beast being locked away — expanded upon with its tease in “The Balrog” a few years later. “Trapdoor” is the most famous and most played song from the album, with its mysterious lyrics and unique instrumentation making it a fan favorite from their 2015 output and beyond. It was released as a single on September 22nd, 2015, and then as part of Paper Mâché Dream Balloon on November 13th, 2015. It also appeared on an ATO Soundcloud sampler and a separate two song flexi-disc sampler released at record stores alongside the album proper. An instrumental version featuring an outro with double bass noodling was released as part of the deluxe edition of Paper Mâché Dream Balloon on October 29th, 2021.
Jason Galea’s music video for “Trapdoor” was released on November 10th, 2015. Starting with a quick shot of the band’s miniatures from the album’s cover in front of a miniature castle, we then see various clips of the band before cutting to Eric wearing a knight's outfit walking to an actual castle. Inside Cavs, Cook and Eric are wearing robes while Joey acts as the dining table with his head surrounded by fruits and vegetables. We see Stu playing flute and singing by candlelight while wearing a ghostly white cloth. Later on, Ambrose is seen wearing a black robe and singing with Stu. The video is chaotic, with fast cuts, flashing lights, shots of various props and filtered footage of the band walking up stairs and singing.
In an interview for NoFilmSchool, the video was compared to the works of Monty Python and Alejandro Jodorowsky. When asked what inspired the video, Galea said “We made this video on tour in Europe. We were waiting to find the right idea or place to make a goofy music video, and one night we played at this massive concrete venue in Hamburg which was a Nazi bunker in World War II. There were some really cool props and bits laying about that were perfect for a ‘Trapdoor’ clip and it all just happened pretty easily over a couple of hours. A few days later we shot the outside scenes at the Nottingham Castle using props from the gift shop. I haven’t watched much Monty Python at all, but in Australia, there were a lot of British programs on television when I was growing up, so from time to time I’ll go into this weird '80s BBC mindset when making videos.” The Hamburg venue he refers to is Uebel & Gefährlich, where the band played on 2015-06-29. The band played Rescue Rooms in Nottingham a week later on 2015-07-06. Footage of the band recording the video was featured in the documentary BOOTLEG HOLIDAY FROM HELL. Eric and Joey’s costumes from the video were later referenced on the poster for the band’s gig at the UNSW Roundhouse on 2019-07-05.
The earliest known performance of “Trapdoor” was on 2015-08-23 at the LA Sports Arena & Exposition Park for California FYF Fest, months before the release of Paper Mâché Dream Balloon. No recordings of the song from 2015 exist, though during their 2015 Reddit AMA, Stu said that “Trapdoor” was his favorite song from Paper Mâché Dream Balloon to play live. In 2016 the song was in heavy rotation. These versions are close to the studio version but are much heavier, with growling vocals from Stu, falsetto vocals from Ambrose, light synthesizer work and wah wah guitars. The final performance from that year (that we know of) was on 2016-09-09, after which it would take a long break, although there had been some thought as to bringing it back. In the band’s 2020 Reddit AMA Stu mentioned that he wanted to revive the song after hearing the version from 2016-05-25 (released ten days before the AMA, on Live In San Francisco ‘16). Two years later on 2022-03-05 during The Return of the Curse of Timeland festival, the song was brought back — this time coming out of “Sea of Trees.” It would then be played six other times that year. These versions either came out of other songs like “Hot Water” (2022-04-11) or “The Balrog” (2022-10-10), although other times it was played on its own. These versions often ran longer than the studio version and featured a longer intro, a longer outro, or both. This was brought back for 2023, although the song saw a reinvention with the introduction of an acoustic rendition on 2023-06-04 at The Caverns in Pelham. At the beginning of the year, Stu also joined the band Los Bitchos to perform their version of the song during their opening set.