Blood Lamp, 2009, a single-use light that draws its energy from a drop of blood, by UK artist Mike Thompson, creator of the wifi dowsing rod.
For the lamp to work one breaks the top off, dissolves the tablet, and uses their own blood to power a simple light. By creating a lamp that can only be used once, the user must consider when light is needed the most, forcing them to rethink how wasteful they are with energy, and how precious it is.