What looks like a patch of dead moss on a tree is actually a mass of hundreds or thousands of Daddy Long Legs, also known as Harvestmen. The cluster of arachnids, from the order Opiliones, was found in a tree near a stream in Nogales, Arizona. Boing Boing just posted the video, but it appears to have been on the Internet since 2009 or earlier. There are also photos of harvestmen clusters on the Internet, see here and here. Take a look:
