There is no specific Pokémon that you need to trade Haunter for in order to evolve it.
Trade Haunter with any Pokemon to make it evolve!
You'll need to trade for a Haunter in order for it to evolve into Gengar.
Yes. The pokemon is Haunter. In order to evolve Haunter you will have to trade him with a friend and he will evolve. Just trade back to get Gengar.
You have to trade the Pokemon to evolve it.
You trade haunter to get gengar.
Trade Haunter and you will get a Gengar.
Actually, Haunter does evolve. Its evolves into Gengar when you trade it.
Link trade!!!!!!!!! You have to trade for another Haunter in order for it to evolve into a Gengar
In order to evolve Haunter, u have to trade and it will evolve into a Gengar.
You have to find your friend, you trade your Haunter with another Pokemon and when the trade is done Haunter will evolve.
You have to trade it to evolve it.
trade it then it will evolve