This is a cake I made for my son's birthday

Step 1: Stuff You Need

Cakes
Icing
marshmallows
food coloring
Pans
Spatula
knife
paper template
patience

Step 2: Make Your Template

Draw out what you want to make... in this case an Alligator.
Make sure it fits in the pan.
Figure out how many cakes you need.
Bake your cakes

Step 3: Claws and Teeth

I like to use mini marshmallows
Snip them with scissors, then let them dry overnight.
Put them in the fridge to make them easier to work with.

Step 4: Get Your Icing Together

Depending on your colors, put some food coloring in a tub of Betty Crocker icing
I use a tube to put the icing on.
Sometimes you can buy the tubes of icing with the nozzle kits.

Step 5: Cut Out the Cake

Here's the tricky part. Put your paper template over the cake and use a bread knife to cut out your shapes.

Step 6: Time to Decorate

You can either spread the icing on (I like to do that with the base) or pipe it on.

I like to use the tubes for details. Usually the black blue and reds.

Black doesn't taste very good... so avoid Darth Vader cakes.