Get a link cable and trade/receive a Haunter.
machoke - machamp, haunter - gengar and Kadabra - alakazam
Put in a Pokemon GBA cartridge in the GBA slot (Ruby/Sapphire/Emerald/FireRed/LeafGreen) and then go to the Haunted Mansion in Eterna Forest, inside you will have a very rare chance of finding a Gengar.
Trade A Haunter to Another Game
you cant go underwater in leafgreen!!
Take a gengar to her and you'll find out
you have to traid a haunter
Trade a haunter to a friend then take it back to receive gengar.
Using the dual-slot feature with firered or leafgreen will make it possible to find gengar in the second room from the right on 2F
you cant find gengar if you not have steal trainers Pokemon cheat
Trade it from from Firered or Leafgreen. Or get a gameshark and enter the CORRECT code.
machoke - machamp, haunter - gengar and Kadabra - alakazam
You can't find gengar in the wild, you have to get a haunter and trade it.
Wild Gengar can appear in the Old Chateau if you have Ruby, Sapphire, Emerald, FireRed, or LeafGreen in the GBA slot. In this case, it has a 4% chance of appearing.
Gengar is a powerful ghost type of Pokemon. In Pokemon Platinum it is possible to capture one by going to the Old Chateau.
To get a Gengar you must first catch a Haunter. To evolve the Haunter you have to trade it to another gaming system.
Piplup does not exist in Pokemon LeafGreen or FireRed.
No, you cannot find cyndaquil in LeafGreen.