[escapefromboston]

The GI Joe cartoon movie where Cobra Commander turns out to be a giant snake???

(I liked that movie too)

[SoldierMedic]

He turns into a giant snake after getting hit with some spores. It's a fabulous movie.

A bit of trivia: Duke was supposed to die, but because of children's reactions to the death of Optimus Prime in the Transformers movie, it was decided to have Duke come through in the end.