Here's how and where to find Haunter, Gastly, and Gengar in "Pokémon GO." 

To begin with, players must catch Gastly first. It is worth noting that the said creature has no true form due to its body being made up of 95 percent poisonous gas. However, Gastly consistently shows up as a black, spherical Pokémon encompassed by a purple haze.

Gastly is said to be the original form, which evolves into Haunter beginning level 25 and eventually advances into Gengar when traded. Players, on the other hand, can also hatch some eggs to obtain a Gastly Pokémon. Attack of the Fanboy  reported that Gastly Pokémon requires players to walk 5 kilometers before they hatch.

At the point when fueling up Gastly Pokémon, its combat power will also increase and even accomplish more damage. Thus, the amount of Stardust and Candy needed apparently relies upon the amount Gastly is already leveled up.

It is said that players need 25 candy to evolve into Haunter and another 100 candy to further advance Haunter into Gengar, according to Reddit.

Considering that Gastly is a ghost type, it is expected that the dual-type Ghost/Poison Pokémon will appear in cemeteries, which are typically home to most of the Pokéstops and gyms. However, such claims have apparently been debunked by the game developer, Niantic, Inc.

"Pokemon GO" allows players to use a mobile device's GPS capacity to find, catch, battle and train virtual Pokémon, who appears on the screen as though they were in the same real-world location as they player. Launched on July 6, 2016, the augmented reality game has been downloaded by more than 100 million individuals around the world.