My son wanted a Spidey Cake for his 8th Birthday. I just baked a 9 x 13 chocolate and a 9 x 13 vanilla cake and laid them side by side on a cake board covered with foil. I covered the whole thing with generic white frosting from a can. Then I colored my own black frosting from more generic white frosting. (I recommend using chocolate as the base instead of white).
I piped the web shape onto the cake starting from the bottom corner. Since I am not very good with frosting tips, I simply piped lines of the red frosting into the spaces of the web and then used a spoon to even it out. We used some little action figures we got at a toy store to stick on the web and candy letters to say Happy Birthday!
It turned out to be one of the best cakes I’ve ever made even if it did turn everyone’s mouths purple!