A new event in Pokémon Rumble Rush is called Gengar’s Cavernous Hideout, which is now underway until September 4, 2019. The latest in-game event features the following Pokémon: Alakazam, Gengar, Kadabra, and more (80 different species in total). It features the following Summon Gears: Psychic (Alakazam), Shadow Punch (Gengar), Psychic (Kadabra). Also, starting with this event, the area rank limit is 30 (instead of 25 previously). Area rank 21 and up will feature powered-up versions of Super Bosses you’ve already battled (available until September 4th)
- [Log-in Bonus] As compensation for the maintenance that took place on August 20th/21st, all players can now claim the following as special Log-in Bonus: Poké Diamond x100 (available until September 21st)
Source: Perfectly Nintendo
Pokémon Blog 
One thought on “Gengar’s Cavernous Hideout event now underway in Pokémon Rumble Rush”