Our biofuel cell generates power from glucose sugar in a snail's body. We drill holes through the shell and implant enzyme-coated electrodes in the hemolymph, or snail blood, that naturally collects between the snail's body and shell. Like any battery, ours is based on chemical reactions that create a flow of electrons. One electrode grabs electrons from glucose in the hemolymph. The electrons then travel through an external circuit—including any device we want to power—and end up at the opposing electrode. There, the electrons react with oxygen in the hemolymph to form water. The power output is small, in the range of microwatts, and runs out after a few minutes as the glucose is depleted. After harvesting energy, the snail eats and drinks, restoring glucose levels in its body, and it can then generate power again. The snails don't appear to be harmed by the biocell.