A Bullet Bill Shooter that scrolls up and down and stops to turn around when it hits the floor or ceiling. The extra bit can be set to make it shoot in Mario's direction (which also changes the palette), otherwise, its direction is determined by X position. Palettes and speeds are changable at the top of the ASM file.
The changes I made were aside from the obvious ones (PIXI, SA-1, shared routines) to make the palette editable in the CFG file (at least for the version shooting in just one direction), a couple fixes with the position of the bullet bill and smoke and some code optimisations.
I also added some graphics.
That being said, this sprite surely can be remade sometime.