Electronics is evolving from rigid, flexible to ultimate stretchable electronics in which active optoelectronic materials are required to deposit onto or embedded into elastomeric materials. We have recently demonstrated a powerful solution-based electroless gold coating technology, which enables growth of enokitake-like gold nanowires on two-dimensional elastomeric sheets and one-dimensional fibers for a wide of applications in wearable bioelectronics. Here, we show that such an elastomeric gold coating technology can be extended to three-dimensional (3D) elastomeric sponges. We have successfully grown vertically-aligned enokitake-like gold nanowires (v-AuNWs) uniformly throughout 3D sponge skeletons, leading to highly conductive sponge with a conductivity up to about 1500 S/m. This, in conjunction with embedment of Ecoflex into porous v-AuNWs sponge, leads to a strain-insensitive conductor that only changes about 17.3% in resistance under 50% strain, 83.3% in resistance under 100% strain. The conductor can be stretched up to ~340% strain before losing conductivity. Furthermore, the strain-insensitive sponge conductors are used as electrodes to fabricate elastic supercapacitor which can retain 102% and 99% of initial capacitance under 50% compression strain and 180º bending, respectively. In addition, our gold sponge is also catalytically active and can serve as recyclable 3D porous catalyst (achieving 90% conversion efficiency even after 10 cycles of 4-nitrophenol reduction reaction). The results presented here demonstrate a simple yet efficient wet chemical approach to multifunctional sponge for applications in stretchable electronics, wearable energy devices and catalysis.