New Info?] Looks like Party Hat Gengar will be able to Mega Evolve

Pokémon Go Mega Evolution update and new bonuses, how to Mega Evolve and all Mega Evolutions list

New Info - Mega Gengar and Costume Gengar added : r/TheSilphRoad

Gengar, Pokémon GO Wiki

New Icons for when you mega evolve Pokémon : r/TheSilphRoad

First event gengar was shiny! Kinda weird the mega evolution's illustration doesn't change tho.. : r/pokemongo

BUG] Party hat Mega-Gengar shiny isn't shiny in the preview : r/TheSilphRoad

Shiny Mega Evolution Forms : r/TheSilphRoad

Shiny Mega Gengar Poké Plush - 13 In.

First event gengar was shiny! Kinda weird the mega evolution's illustration doesn't change tho.. : r/pokemongo

Can party hat Gengar megaevolve? : r/TheSilphRoad

MEGA GENGAR RAID in Pokemon Go - Halloween 2020 Costume Gengar

Pokémon Go Halloween 2023 Part 2 event, Timed Research quest steps - Polygon

Pokémon Go event Pokémon list: All costume Pokémon, including party hat Pokémon, flower crown Pokémon and every Pikachu costume explained