Creating and decorating a child's novelty birthday cake doesn't need to be a daunting task. One of the easiest and most successful approaches is to create a 2-dimensional shape of your chosen animal, car, or storybook character. By sticking to 2-d (rather than 3-d) you avoid any possible collapses of cake and don't need to put in supports - but you still achieve a great look.
Additional advantages of this approach ensure you have enough cake for all your guests. The pukeko above was draped in colored fondant.
The steps in a 2-d cake creation can be seen in the following pictures of the Gruffalo cake we made for our nephew - it involves baking a large slab of your (or the birthday girl or boy's) favorite cake flavor (big enough to cut out the desired shape). Print out an image of the shape you want as a guide and then cut out (sculpt) with a sharp knife and cover with a layer of ganache ready for the top layer of fondant or further ganache decoration.
And then have fun with the decoration - for the Gruffalo we used mostly ganache for the fur (a fork creates great fur effect) and some smaller fondant features, such as the eyes, teeth and a small fondant mouse.
And what better reward for all that effort than seeing the delight of the birthday boy when he sees his cake and then blows out the candles!