Dopleganger

The Dopleganger, is the villain, of the Scribblenauts series. He looks the same as Maxwell, except with a blue Rooster helmet, and darker clothing.

Super Scribblenauts
In Super Scribblenauts, The Dopleganger, plans to steal all the starites. Maxwell, then gets all of the remaining ones, and slings them at him in a space battle. The Dopleganger, is then gone, until Scribblenauts Unmasked.

Scribblenauts Unmasked
In Scribblenauts Unmasked, The Dopleganger attempts, to take over the DC universe. With the help, of some Superheroes, Maxwell deafeats him and returns to his own world.

Trivia
The Dopleganger, is also known, as Maxwell's clone When "Maxwell" is typed in the first few games, The Dopleganger will appear.