Haunter evolves from Gastly starting at level 25. To evolve Haunter into Gengar, it must be traded to another player; it does not evolve by leveling up alone
. In summary:
- Gastly evolves into Haunter at level 25.
- Haunter evolves into Gengar when traded.
This evolution method is consistent across main series Pokémon games, including Pokémon Scarlet and Violet
