The phrase se ji shi kong comes from Buddhist teaching, most famously expressed in the Heart Sutra, where form is described as emptiness and emptiness as form. As a standalone sound, it circulates online as a short spoken clip rather than a song or film line, and creators reuse it precisely because the words carry centuries of meaning in only four syllables. That contrast between ancient philosophy and fast meme editing keeps it useful for ironic, reflective, or unexpectedly serious moments.