You can consider replacing the essence of this system with ice light

But Shigeru Miyamoto couldn't let go of the fantasy he had created

So in the final stages of development he managed to get rid of some bugs
With over 300 bytes of space left he finally managed to sneak Fantasy into the game. Without the president's approval Fantasy is not part of the official compilation of 150 Pokémon and will only be found under very special conditions. And because the bug was not cleared up it is only possible to find it in some of the cassettes most of which are not available in any way.