Within the Pokmon online game sequence, Haunter is a Ghost/Poison-type Pokmon that evolves into Gengar. There are two strategies to evolve Haunter into Gengar: buying and selling it with one other participant, or leveling it up whereas it’s holding a Reaper Material.
Buying and selling Haunter with one other participant is the best technique of evolution. As soon as the commerce is full, Haunter will instantly evolve into Gengar.