Let's you carry sprites between rooms, whether Mario is holding them or they are in Yoshi's mouth, without them disappearing. I also changed some of SMW's sprites so they don't re-spawn when you bring back to the same room. Works with custom sprites.
Tested with Asar v1.71, SNES9x v1.58, in both normal and SA-1 ROMs. Also tested custom sprite respawn prevention with PIXI v1.2.9 and GIEPY v1.0.2.
In order for a certain sprite to actually not respawn, its state should match the initial state in which the original sprite is placed (e.g. I take a Koopa shell through a pipe, and if I kick or kill it and go to the point it's originally placed, it will respawn). Other than this really small quirk, patch works nicely, thus it's accepted.