Opiliones (which we call Daddy Long Legs in my neck of the woods) are a species that most people mistake for spiders, but which are actually their own whole classification of insects. They are a fascinating (if creepy looking) genus that have a number of odd habits, including doing this…
Mathew Cobb has more videos and a great writeup on what makes Opiliones different from spiders on which you can find here. In the links below that article, I also found a great Flickr page with images of Harvestmen from around the world, some of which are really really freaky looking. (There are like 10,000 different species!) My personal favorite is probably the “Jason Mask” Harvestman, which looks like it walked off the set of “Jason vs. The Thing” and would be terrifying if it wasn’t so tiny.
P.S. If you need something to keep you awake at night, watch this. 😉