Okay my Best Friend's mom is wanting me to make a surprise birthday cake, a shark cake.
I plan on making the shark out of cereal treats and I'm going to put it on a sheet(cake), but it needs to be done by this Saturday. How should I store it? How many days should I start before Saturday?

For covering it, I was thinking chocolate mold...But would Fondant be better?
Thank you!

I personally would start working on the shark soon, no later than Wednesday - or sooner if you have trouble with sculpting. Were you asking about using modeling chocolate? You could use either modeling chocolate or fondant, but you should stick with whatever you have had the most experience in and are the most comfortable with. Something like this shouldn't have to be refrigerated, though I would wrap the rkt in plastic wrap until it is covered in M. chocolate or fondant. HTH!