okay, so i have just been asked to make a cake for a guys 70th birthday! they want it Halloween themed. i know how to use butter cream and royal icing. my idea is to do a sheet cake and cover it in orange butter cream and in the conner i wanted to do a spider "crawling" off the cake and maybe 2 littler ones underneath it. my question is should i use royal icing or butter cream for the spiders? Also, what is gum paste? is it like royal?

I would use buttercream for the spiders. The buttercream will dissolve royal icing. Add a little bit of meringue powder to the black to prevent bleeding.

Gumpaste is like smooth sugar play dough. It's great for molded decorations, flowers, and other delicate decorations. Royal icing can be piped like buttercream or thinned for fill in decorations. It crusts quickly and then dries hard.

HTH
Michele