You have to complete each level 3 times using different objects. It is possible.
Complete Advanced Mode on all puzzles & actions
change to an avatar
To unlock the last avatar in Scribblenauts, you must get a gold star on every level. This means completing the level three times in a row without using an item twice. The avatar is the original Scribblenaut. To see the avatar, type "Scribblenaut."
go to options then press avatars and voila choose whatever you bought
Avatar: The Last Airbender was not based on a book.
avatar the last airbender
Avatar: The Last Airbender
For the last puzzle level of Scribblenauts, you don't have to write anything, just head towards the Starite and the doors will open for you automatically.
The last season of Avatar: The Last Airbender concludes on July 19th (2008).
you can only go into the avatar state on the last boss level after you destroy the robot.
You can get "Avatar: The Last Airbender" episodes on iTunes.
There is a button the top one that says avatar but so far the only one u can switch too is a god, maybe u have to do more levels or something idk