The creek represents a solution reaction system. The crab and the crayfish represent a tridentate Schiff base ligand and a bidentate benzimidazole ligand, respectively. These ligands exhibit a competing trend in the formation of cobalt clusters. Two heptanuclear disks are obtained when a single ligand is employed, following a stepwise assembly: {Co1}→{Co2}→{Co4}→{Co7}. A mixture of the two ligands results in a butterfly‐structured tetranuclear cobalt cluster through the following steps: {Co1}→{Co2}→{Co4}. Competition, assembly, and transformation were observed during the assembly process of the Co4 cluster with mixed ligands. More information can be found in the Full Paper by M.‐H. Zeng, et al. on page 7906.