The GRASP Lab at the University of Pennsylvania is a perennial PopSci favorite. Yeah, yeah, we’ve all seen robotic quadcopter drones before. But these tiny, so-called “nano quadrotors” are kind of blowing my mind right now. Dial the video below up to about 0:40 and you’ll see why.

We’ve written extensively about “swarming” robots before, but this is a serious swarm if we’ve ever seen one—right down to the high-pitched cacophony of rotors that sounds eerily like a hive of bees moving en masse. But it’s the way these nano quadrotors swarm—seemingly aware of each other and of each individual’s place in space—that’s truly fascinating.