When extremely intense laser radiation hits the golden foil (dense vertical strip in the middle of the frame), some interesting things start to happen. First of all, the gold ionizes - it turns into some hot plasma-like mess; then, the laser keeps on drifting through the foil forming a channel of insanely charged particles. And eventually, having all its energy given up to the medium, the radiation traps itself in the beautiful golden bubbles. The whole process of the bubble formation is useful for acceleration of the high-energy ion beams. These beams are being actively implemented in medical centers around the world to treat cancer by cauterizing tumor cells.