"Mysterious Trap" is an enigmatic piece in natural C minor and 4/4. Its melody is based on perfect consonances (fourths, fifths and octaves), with many ornaments in between. The melody is played twice, first by an oud, and then an oboe with a persistent countermelody playing in tandem. The harmonies of the melody continue during the transition to the second section. Here, a flute and orchestra bells play the melody in E minor. A piccolo brings it another octave up. The lower registers join back briefly, and a transition with an extended chord progression ends in a rising A-flat major chord before leading back down to the original height, where the chords persist a little longer. The track then loops.
The theme is present inThe Sound of Kirby Café, in Track 8: "Sweet Honey, Pitiful Blooming / Mysterious Trap ~ The World to Win", where it's paired with "The World to Win" in a guitar and piano duo medley.