can anyone help me? rice krispies or cake? any help would be great just dont know where to start or end... TIA

Well, you CAN do it all in cake and fondant. Just one baby step at a time. Start with the basic shape, a dome on top of some rounds, make sure you have supports in every 4" tall, and then start carving the basic shape. When that is done, I would cover with BC, and then add on the straight pannels, and the round cylinders, and then cover THOSE in fondant or BC, and then air brush, or cover in colored fondant or in colored BC.

I sure hope that makes sense. I also hope it helps! I totally stole someone else's Halo 3 helmet cake. It's in my photos. But that is pretty much how I did that cake.