It was previously stated that the stages in the Wii U version of the upcoming Super Smash Bros. would be based on console games while the stages in the 3DS version would be based on handheld games. As we've seen already, that "rule" is not set in stone. Consider the lastest 3DS stage reveal, which sources the Paper Mario series, only one game of which was on a handheld.
Director Masahiro Sakurai explains the new inclusion:
He also reveals that this stage will constantly transform:
Since the stage is paper, it transforms when it folds over and opens up again. This ship is the S.S. Flavion from Paper Mario: The Thousand-Year Door.
You can check out both images in the gallery below. Afterwards, hang on tight for Super Smash Bros. for Nintendo 3DS to arrive on October 3. The Wii U build will come out later in winter.