..."box" battle?
Edit: Also, Baby Bowser seems to have be redesigned to look exactly like Bowser Jr....again. After he was unredesigned to look like regular Baby Bowser again in Yoshi's Island DS. Can they just not make up their minds?
Edit 2: Also also, Artoon/Arzest really has a thing for sudden time-traveling Bowser, it seems.
Edit 3: So uh, walking pipe dude was really a time-traveling Mario all along? I guess that's kinda new. Makes me sad such an idea was wasted on such a lazy game.