This is one of the hardest models I have ever folded: Robert Lang's Tarantula.
This is my second attempt to make this origami model (the first one was a huge failure.....I was too stupid then to know that I can cut a 1:3 paper without folding a square first...And now.....eh.
As you can see it didn't turn out very much like Lang's version (once again, because it's by LANG) but we could say that it's a tarantula about to jump :) (I stated the same thing to my friend and then he shouted at me XD....yes he's a he).
The diagrams can be found in "The Complete Book of Origami" authored by LANG himself.
Remember the useless difficulty level I usually give? Let's apply it here :D from a scale of 1-10, 10 being the hardest, I would give a 10, 583, 759, 234. :) (joke)
Anyways, it was a fun model to create :)
Oh yeah, you can also find a tutorial of another of Lang's tarantulas (a different model, not featured in this post) which apparently looks more complicated.