I'm not sure.
But if you catch a Gastly in either Burned Tower (Ecruteak City) or in Sprout Tower (Violet City) and train it, you Gastly will evolve into Haunter at level 25. To get Gengar, trade your Haunter and it becomes Gengar.
When you trade him/her like in all other generations.
You'll need to trade for a Haunter in order for it to evolve into Gengar.
You have to trade it and it evolves.
Haunter only evolves into Gengar through trade. If you're using a generation 4 Pokemon game you can deposit Haunter into the GTS and trade for any other Pokemon in the GTS, then take back your Haunter and it will evolve.
You cant. You have to catch a gastly then envolve it to haunter then trade with someone and trade back haunter will envolve to gengar!
Haunter evolves into gengar once you trade him.
yes
There is no NPC who you can trade a Haunter to for a Gengar in Pokemon Crystal. To get Gengar you will need to trade with another player or a copy of Pokemon Gold, Silver or Crystal.
You have to trade it to an other game for it to evovle.
When you trade him/her like in all other generations.
i will but u get me the Pokemon above
if the other person wants to trade there haunter to evolve and haunter evolves when you trade it
You trade haunter to get gengar.
Trade Haunter and you will get a Gengar.
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.
You can trade it to a friend.