i am planning on making a cake like this
It will probably be 8 & 6 my question is do you think I need some type of support under cookie monster? I am planning on making him from RKT.
I probably would, but then I'm the paranoid sort!
RKT are MUCH heavier than you would think....
I would definitely put Cookie on a separate cakeboard to plate.
To give you a better idea on how to sculpt Cookie.. Here's a 3D RKT Elmo tutorial:
(Courtesy of cake-angel.)
Everything you need to know to bake, assemble and decorate tiered/stacked/layer cakes:
I would even consider constructing your cookie monster on a dowel so you could stick it right into the top tier. then it would have some stability and not flop over from the weight. I made a hulk cake (in my pictures) with a RKT fist, and even that got a little wobbly. If I do it again, I would definately construct it on a dowel. You can put the dowel in some styrofoam while you're working on it. HTH