Introduces functional gill structures in the neck — three pairs of branchial slits with vascularized gill filaments capable of extracting dissolved oxygen from water. The gills are supplementary to lung breathing; the user can breathe air normally and switch to gill respiration when submerged. The gill slits are visible — vertical openings along the sides of the neck that flex with each breath-cycle when submerged. On land, they close to thin lines that are noticeable but not immediately alarming. Crucible Genomics' full installation includes enhanced skin moisture retention to prevent gill desiccation in dry environments. The modification enables indefinite underwater breathing in oxygenated water. In GLMZ's polluted harbor, water quality limits practical gill-breathing to 2–3 hours before the filtration capacity of the gills is overwhelmed by contaminants. The modification is rare, expensive, and visually dramatic — gill users are immediately identifiable.