A collaborative team led by Caixia Gao at the Chinese Academy of Sciences revealed the evolutionary origin of Type V CRISPR-Cas systems through the discovery of transposon-CRISPR intermediates (TranCs). These intermediates, bearing features of both TnpB transposon nucleases and Cas12 enzymes, employ CRISPR RNAs to target DNA, illustrating how RNA splitting events catalyzed the emergence of versatile Cas12 immune effectors. This insight enhances fundamental understanding of CRISPR adaptation and supports expanding genome engineering technologies.