There are currently two raids that award Costume Gengar in Pokémon GO: Mega Gengar raids that take multiple trainers to take down, which also award Mega Gengar Energy and… well, Costume Gengar raids. The latter are Tier Three raids able to be completed by solo trainers. Since we already have a full Mega Gengar Raid Guide, now let's dive into what solo trainers need to bring to the table to defeat the Tier Three Gengar in Pokémon GO.
To defeat Costume Gengar, going in with the team you created for the Mega Gengar Raids based on our counters guide will be perfectly fine. However, there are small tweaks you can make to your team to specialize it to Gengar's Tier Three level. For this lower level raid, regular Mewtwo with Confusion and Psystrike take over from Mega Gengar as the top non-Shadow counter. This means that it won't make a huge difference if you have a Mega Gengar on your team, so if you're not going to do a bunch of raids in the next eight hours of Pokémon GO gameplay, skip out on the Mega Evolution for the time being. Replacing Shadow Tyranitar as a top counter are Shadow Metagross with double Psychic-type moves and Shadow Weavile with double Dark-type moves. Other sure bets are:
- Latios (Zen Headbutt, Psychic)
- Giratina Origin Forme (Shadow Claw, Shadow Ball)
- Darkrai (Snarl, Dark Pulse)
Any powered-up Psychic-type or Dark-type Shadow Pokémon will also do work against Gengar. When looking for a 100% IV Pokémon, Gengar's top CP in raids is 1644 in normal conditions and 2,055 in boosted conditions. If you're looking for an easy-to-raid Shiny check for Costume Gengar, this is going to be a much better bet than Mega Gengar, as that is currently the most damage-dealing raid boss in Pokémon GO. The Shiny rate of Costume Gengar is not currently known.