Sun et al. found that melanoma cells lacking STIM1 and Orai1 sprouted about half as many invadopodia, the extensions that cancer cells use to bore into and dissolve the ECM, as did controls. But it takes more than an influx of calcium to induce the protrusions. Compounds that induce a surge of calcium into cells inhibited invadopodium growth. Instead, invadopodium formation requires oscillating intracellular calcium levels. Depleting STIM1 and Orai1 suppresses these cycles.