A Psychic near the entrance to Victory Road.
There is no trainers that is wearing a Gengar costume. There is only trainers wearing Pikachu costume. If you are meaning trainers who have gengar... i wont be sure about it but if your also trying to say how to get a gengar, you have to find a gastly train it and evolve it to haunter and you have to trade it with a friend to evolve it and the friend has to trade it back to you to have your gengar back.
you have to trade a haunter and it will evolve into gengar.
you cant find gengar if you not have steal trainers Pokemon cheat
Psychic Bryce has a gengar in Pokemon platinum.
Yes at the Hearthome gym leader's trainers.
Gengar is a powerful ghost type of Pokemon. In Pokemon Platinum it is possible to capture one by going to the Old Chateau.
phycic type trainers, in victory road
A trainer in Victory Road has a Gengar.
gengar
trade from other games
gengar
A Gengar can be seen in a battle with Psychic Bryce in Victory Road.