chainin' huanter in the ghost trial site to get gengar, how do I do it? meesa wanta bombad ghosta
The easiest method - Find a way to get Scrappy Pancham (chaining, gts, etc) -Now Teach the Pancham or Pangoro false swipe -Head to Thrifty Mega Mart -Chain off of Haunter until you get Gengar (Gengar can only appear through Haunter) Source For Encounter
Well, first, get the wild Haunter. Then bring it's health to a very low level. It will start calling for help. Kill what it calls untill a Gengar appears. That's how I did similar stuff (specificaly, to get a Chansey)