For the Ben 10 cake I made a round, 20cm chocolate fudge cake with real 70% cocoa solids chocolate and layered it with chocolate fudge. The chocolate fudge is made by melting chocolate with cream, cooling it and then adding some homemade vanilla buttercream to it to sweeten and thicken it.
There are 4 cake layers and 3 choc fudge layers. I then coated the top of the cake first with buttercream and then with homemade fondant icing. The Ben 10 figure I cut out the outline from a picture from the internet from fondant icing strengthened with gum tragacanth and, when dry, painted Ben with edible colours.
Related cakes:
Coolest Ben and Holly Birthday Cake 
Cool Homemade Ben 10 Watch Birthday Cake for a 6th Birthday 
12+ Coolest Peppa Pig Cake Ideas 
12+ Coolest Minnie Mouse Cake Ideas 
Cool Homemade Ben 10 Birthday Cake 
Cute Homemade Ben 10 Character and Logo Birthday Cake 
12+ Coolest Frozen Birthday Cake Ideas for the Ultimate Frozen Theme Party 
Coolest One Eyed Minion Cake
very cool.