I've been looking at photos of cakes with volcanos and have seen both carved cake and rice krispy treats used. I would like to know if anyone has any recommendations as to which to use.

My volcano is going to be on top of a half sheet rectangle and I plan on covering it with fondant and then melted wilton's candy to form the lava. Also (possibly most importantly ) I'm going to put a plastic juice cup inside to make dry ice "smoke". I will probably just use a box mix for the cake--I'm super amature-- unless someone has something else to recommend.

What are the pros and cons of each medium?
Any other tips?

I used only cake when making a volcano cake because it was the only cake on the display - so it was what we ate. Rice Krispies may be easier to get the shape of the volcano - this depends on how comfortable you are with sculpting cake. I used a tall straight vase for dry ice and the children loved it - we actually stopped the birthday party so the men in the family could put on a show with the remaining dry ice. Anyway, back on topic - if you are not going to eat the volcano, i might choose to use rice krispies.

You can see what i did at:

http://www.cakecentral.com/modules.php?name=gallery&file=displayimage&pid=1265593

Good luck! Can't wait to see how it turns out!

I went with rice krispies and it was great! It only took about half an hour from cooking them up to forming the volcano too. I spent a good amount of time with the fondant and candy melts, but I was really happy with the results!
here it is.
http://www.cakecentral.com/modules.php?name=gallery&file=displayimage&pid=1499042&sub=1499050