A Chilling Curse!

Strange phenomenon have been happening at Sakuragi's Laboratory lately such as rooms getting ramsacked. On hunting down the problem, Ash & Go find out that the culprit is none other than the Gengar they had encountered previously. Ash & Go both intend to catch the Gengar but Ash starts acting very weird and even almost falls down the stairs. Is Gengar responsible? Will they stop Gengar?