You can use this API for magikoopa, and you can choose which section which the magikoopa can appear.
To use:
1. Extract the files from the download, and copy it into the level's custom graphics folder.
2. Make a new file in the custom graphics folder called "lunadll.lua" (make sure the extension is .lua)
3. Then add this to your lunadll.lua code:
magikoopa =API.load("magikoopa")
4. However the magikoopa will only appear in section 1 by default, so if you want it to appear in other section you would need to add this:
magikoopa.section = {list of sections}
For example if you want the magikoopa to appear in section 5 and 6, then you need to do this:
magikoopa.section = {4,5}
5. Also if you want to change the enemies that appear from the blocks, you would need to add this line of code:
magikoopa.enemy_list = {list of npc ids}
For example if you just want SMB3 goombas and koopas you could use:
magikoopa.enemy_list = {1,2,4,6}
6. You can also edit which blocks will be affected by the magic:
magikoopa.block_list = {list of block ids}
For example you want the SMB3 wood block to be affected, you can use:
magikoopa.block_list = {1}
An image (quite outdated):
https://www.mediafire.com/?z53dpubkx02unqk