If you mean Ho-Oh, then that's a no :(. Without an Action Replay I'm Afraid that Ho-oh is impossible to obtain in Ruby and Saphire. Unless you consider trading the Ho-oh from Pokemon Colloseum obtaining a Ho-oh.
You'll need to trade for a Haunter in order for it to evolve into Gengar.
in any Pokemon you evolve haunter by trading
Get a Haunter and teach it Scary Face. Give Haunter a Quick Claw and take him to Mersprit.
Haunter can level up and evolve. It evolves by trading with another player.
You have to trade it and it evolves.
There is no need to trade to evolve Haunter in Light Platinum, the Pokémon Ruby hack. It will simply evolve as you level it up.
The way to evolve Haunter has been, and will always be, by trading. If you have a Haunter in Pokemon Emerald trade it to Sapphire, Ruby, Fire Red or Leaf Green and make sure he isn't holding an EVERSTONE as that will prevent its evolution.
Yes, Haunter is a very good Pokemon
Haunter is a ghost type Pokemon
Mismagus,manphy,mewtwo,mew,gastly,haunter,azelf,mesprirt,uixe and......Dialga,palkia and giratina!
look in the Pokemon tower in lavender for haunter. note, haunter is hard to find in the Pokemon tower
You trade haunter to get gengar.
Haunter evolves when traded
Trade Haunter and you will get a Gengar.
you can't find haunter in Black
You can get a Haunter in Almia Castle.
You will need to level up Haunter to level 50 to evolve it in Pokemon Resolute.