The ChouChou Robotic Butterfly is just like a real butterfly, except it can live forever. Or at least until its battery runs out. You won't even know the difference, just watch it fly. [Japan Trends]
This is bull-Pu! Butterflies have been around since the dawn of chicken mcnuggets. But I depress.
I believe this uses an unusual material allow (metal) that fluctuates when the charge (battery) varies. It has been around a while, and it quite interesting.