A pack with some very customisable question mark blocks including a power up dependant block (similar how the flower and feather ?-blocks from the original game act like), a block to spawn enemy sprites, giant versions of them and a giant coin block.
You can change the sprite (obviously), the initial sprite state (for carryable and some other sprites), the power up out of block/ stun/ random sprite timer (depending on the sprite), the sound effect, some bounce block settings including properties too and even whether the block is dependand from the item memory or not (requires the included object).
Be aware that due to unoptimised routines (not my fault, really), the giant blocks can cause black lines on top of the screen or glitch the HDMA for one frame.
Read the readme for more information.
Also thanks for LX5 for two routines and the Yoshi egg blocks.
I have got an important note if you use custom power ups: The initial sprite state has to be set to 1 from then, not 8 like the vanilla power ups do.
Also, you have to replace the #$10 at LDA #$3E : STA $15AC,x on the bottom with #$3E, else the power up gets pushed out of the wall.
@toad64: It's a patch which allows you to create custom object. The main purpose with the blocks is the item memory i.e. the game knows in the level whether the block and sometimes sprite were activated or not.