The Cheetah is pretty impressive; the fact that it could outrun a human makes it significantly more unnerving. Speaking of unnerving…
DARPA is developing low-cost silicone robots capable of adaptive camouflage.
http://www.youtube.com/watch?feature=player_embedded&v=LpOl_pEmRqs
“by introducing narrow channels into the molds through which air and various types of fluids can be pumped, a robot can be made to change its color, contrast, apparent shape and temperature to blend with its environment, glow through chemiluminescence, and most importantly, achieve actuation, or movement, through pneumatic pressurization and inflation of the channels.”
What’s worse than a robot that can outrun you? One you can’t see.