You have to trade it to an other game for it to evovle.
haunter learns it at level 34
If you mean Gengar (Fantina the 5th gym leader has one ) You have to evovle Haunter by trading it.
Gastly evolves into Haunter at level 25, then trade it and it will evolve again into Gengar.
You evolve it into Haunter at Level 25. To evolve Haunter into a Gengar, you need to trade it.
Haunter does NOT evolve by level. You evolve Haunter by trading it with a friend, and then they trade it back to you. Hope I helped :)Haunter evolves from Gastly at level 25.Haunter evolves into Gengar through trade.Haunter evolves into Gengar by trading it.
Level 16
On level 20.
level 40
Level 30.
Level 32.
level 26 ^^