Naturally-occurring misperception can help establish the ecological validity of laboratory findings of speech perception and generate new hypotheses. In this study, we report on a corpus of misheard German sung speech which contains instances of misperception reported by individuals. We validated the corpus by examining segmental confusions, and word mis-segmentation. Approximately 1,000 segment confusions were found. Our naturalistic segment confusions were significantly correlated with acoustic distances (r = 0.559) and with speech-in-noise-induced confusions in an experimental study (vowel: r = 0.364; consonant: r = 0.210). Our mis-segmentation patterns only partially confirmed the rhythmic segmentation hypothesis and findings from previous studies. While boundaries inserted before strong syllables created content words following the preferred rhythmic properties of German, we find an unexpected amount of boundary deletion before strong syllables, resulting in nonce percepts which might reflect the expectation of listeners with neologisms in lyrics.