The creature was created by the Delightful Children From Down The Lane. When they were at the stadium ready to eat their cake while all the other kids in the stadium get nothing, Sector V shows up to make sure everyone in the stadium gets a slice.
The cake though comes to life in a gigantic monster which the Delightful Children call the Pound Cake. Just as the Delightful Children were about to beat up Sector V with their cake monster, Lizzie Devine shows up and destroys the cake with her ship.
After the Pound Cake is destroyed frosting flew all over the stadium and the Delightful Children started to cry and Numbuh 1 says, "Thanks for the cake delightful dorks. Well see you next year, and make sure to bring enough cake for everyone."