So, FP asked me on steam a month ago to make that mod. I made it, gave him and then forgot about it. Then today, FP made me unforgot it.
This mod make mushrooms boxes act like in NSMB Wii: If you're in singleplayer, they will act as normal and dispense 1 mushroom/flower.
If you're in multiplayer, it give as many mushrooms/flowers as players. And the mushrooms/flowers "jump" in a random direction.
Screenshots:
