An improved version of my second entry in the ASM Contest. This uberasm generates a window that splits the screen into two sides. one side has black foreground and sprites while the other has black background, coupled with the palette in the download files it makes for a stylish black and white effect. SplitWater.asm makes Mario and sprites act like they're in water on the right side of the window while SplitMushroom makes Mario big on the right side and small on the left side. To make Mario pitch white when this uberasm is active insert the patch in the download files with Asar. If you do not want glitched level transitions use the file on the folder "gamemode 0F" in uberasmtool as, you guessed it, gamemode 0F. You can tweak every variable of the effect by opening the asm files and changing the defines, Enjoy!
Rejecting because from the testing I've done, while the raw mechanics of getting/losing a mushroom and enabling/disabling water physics work, the windowing effects at play seem to bug out pretty hard after a bit of time using them. Primarily happens when you try threading the border, at least from the testing I did. It causes pretty hard screen flickering and vblank overflow in some instances. If you want videos of what I'm referring to (in case you're unable to replicate this), DM me for some clips.
As for SA-1, I tried inserting the patch onto an SA-1 rom and it threw a define error, so the SA-1 hybrid defines must not have been done properly. I suggest you test this out on both lorom and SA-1 before resubmitting, along with fixing the flicker issues. Definitely an interesting piece of code though and I'd love to see this get accepted eventually.