My 5 year old son loves Perry from Phineas and Ferb. In the past I have used Wilton character pans, but I looked everywhere (online included) and none exists. I could not disappoint him, so I went and bought a 12″x18″ pan.
I just used cake mix boxes. I had to use three boxes to fill up the pan. I had never used more then one box, so I thought it was going to be a massive decorating task. It turned out to not be bad, probably because there are not a lot of colors in Perry.
Once the cake was baked, I leveled out the top. I then worked right on the cake board. I got a picture I liked of Perry, and sketched it out free-hand with white frosting on the cake. For all my frosting work I use the disposable clear cake decorating bags with Wilton tips and connectors. I then trimmed off excess cake to make it appear like it was from a shaped pan. I then used chocolate frosting in the base areas to make Perry appear stealth, since he is a secret agent and always hiding. I then colored the frosting and filled it into to bring Perry to life. I also just used store frosting. The chocolate I had was the whipped kind, and that seemed to work better then the white creamy kind I used.
Everyone especially my son loved the end result!