[Other] Replace the ??? Pokemon

[AmazingCharizard]

Hey guys, so there are some ??? spots after Celebi in the pokedex. Is it safe(or possible, haven't tried yet) to replace them with Pokemon?
I don't want those Pokemon to be catchable, they should be special Pokemon that should only be owned by a foe.
I think DarkRisingGirl did this in her hacks but is it even safe?
Thanks in advance!

 

[Spherical Ice]

Which ROM are you hacking? If you're using FireRed, it may be easier to simply expand the Pokédex; there is a tutorial by DoesntKnowHowToPlay which details how to do this, and karatekid552's tool, Gen 3 Hacking Suite, can do it for you with the push of a few buttons. Overwriting the 25 slots is far less safe and more of a pain than simply expanding, at this point, particularly if they're not going to be capturable.

 

[AmazingCharizard]

First, thanks for the super quick reply.
Yeah, should have mentioned that it's FireRed US 1.0 :)
Then I'll have a look at expanding.

 

[Dinoweed]

Don't overwrite those slots I believe they're the other forms of Unown and doing so will mess up your game. Always make sure to test things out on a backup copy of your game!