Lethal Frisbee UAV was cool, but we just found something that might in fact be a bit sweeter. Meet the "Phantom Sentinel," the latest from VeraTech Aero in Minnesota, which is a boomerang-like device for spying on our crafty foes on the other side. Apparently, as the UAV rotates it becomes nearly invisible in the sky while its cam takes quick snapshots of the scene below, then transmits them back to a soldier on the ground. We're assuming that those crazy goggles the other G.I. is wearing in this photo are able to translate that dizzying number of spinning images to something that a human brain can make sense of.