The stomatopod Odontodactylus scyllarus uses weaponized clubs like appendages to attack its prey. These clubs are made of apatite, chitin, amorphous calcium carbonate, and amorphous calcium phosphate ordered in a highly hierarchical structure with multiple regions and layers. We follow the development of the biomineralized club as a function of time since formation using clubs harvested at specific times since molting. The clubs are investigated using a battery of techniques to unravel the biomineralization history of the clubs. Nano focus synchrotron x-ray diffraction and x-ray fluorescence experiments reveal that the club structure is more controlled having more regions than previously thought. The recently discovered impact surface has crystallites in a different size and orientation compared to those in the impact region. The crystal unit cell parameters vary to a large degree throughout individual samples, indicating a large degree of chemical substitution variation, EDS and Raman spectroscopy show that this variation cannot be explained by carbonation and fluoridation of the lattice alone. X-ray fluorescence and mass spectroscopy show that the impact surface is coated with a thin membrane rich in bromine that forms at very initial stages of club development. Proteomic studies show that a fraction of the club mineralization protein-1 has brominated tyrosine suggesting that bromination of club proteins at the club surface is an integral component of club design. Taken together, the data unravel the spatio-temporal changes in biomineral structure during club formation.