i will be doing a nightmare costume for 08 but i need help in making his arm what materials should i use how should i make it etc, help please! also any pictures of nightmares transitional costume where he is in between siegfried and nightmare would be Very appreciated
If you're making any kind of deformed arm such as Nightmare's, I would suggest using plaster, since it's the easiest to form and paint. Cardboard isn't as malleable, and it's 2D, so I wouldn't use that unless I had to.
You should hallow out the plaster so that your arm can fit in it, and shape it so it's like Nightmare's. Paint it, too, for the right effect.
Hope that helped ^^; I'm not a very professional cosplayer, though; that's just what I do.