If you get all 13 skulls you get the Hayabusa armor
So if you need any help, just post!

In Halo 3 you can get 13 different skulls. only 12 of the make the game harder, the other one is just a comic effect. if you kill a short alien with a head shot confetti comes out and you hear little kids screaming. If you need any help just post on my blog.