We report the synthesis of two new cluster anions, [Cu-4@E-18](4-) (E = Sn, Pb), in which a Cu-4 subunit is incorporated into a continuous E-18 tetrel cage. Both anions are characterized by X-ray crystallography and mass spectrometry, complemented by quantum-chemical calculations that highlight the relationships to known Zintl clusters, including the stannaspherenes and plumbaspherenes [M@Sn-12](q-) and [M@Pb-12](q-), the Matryoshka bronze [Sn@Cu-12@Sn-20](12-), and also [Pd-2@E'(18)](4-) (E' = Ge, Sn).