Gengar was released with the game launch on July 6th, 2016.
In the wild, maximum capture CP of Gengar is 2,467, however it can reach 2,672, if encountered Pokémon is boosted by current weather.
Between October 26th and November 1st, 2016, Gengar's global spawn rate was significantly higher during the Halloween 2016.
Between October 20th and November 2nd, 2017, Gengar's global spawn rate was significantly higher during the Halloween 2017.
Between October 23rd and November 1st, 2018, Gengar's global spawn rate was significantly higher during the Halloween 2018.
As a former 3rd tier Raid Boss, Gengar's CP was 21,207. Its maximum capture CP in Bonus Challenge was 1,644 and 2,055 when encountered Pokémon was boosted by weather.
Gengar was available during a limited three-hour Special Raid Challenge on November 3rd, 2018. All Gengar obtained during the three-hour window knew the fast attack Lick and the charged attack Psychic.
Its was a 4th tier Raid Boss and has Raid CP of 31,256 during the Special Raid Challenge.
Shiny form of Gengar was released on Special Raid Challenge.