Kasper Moth-Poulsen shows off the solar collector his team used to test its liquid battery.

Researchers 3-D print a green spiral of cyanobacteria onto a mushroom. The microbes give off electrons when exposed to light. Those electrons flow into the black graphene ink to produce an electric current.

A special pen heats the blue ink on this rewritable paper. As the ink warms, it turns clear. The white paper beneath reveals a written message.

Parasites belonging to the species Naegleria fowleri, sometimes known as brain-eating amoebas, can destroy brain tissue — and kill human victims within a week.