Things You'll Need
Instructions
Visit the Mount Moon map by completing missions and matches on the maps prior to it. Reaching Mount Moon as a level 14-20 makes catching a Gengar in the wild easier, but lower levels should build your experience points up with some practice battles.
Explore the Mount Moon region to attract wild Pokemon into battles with you.
Encounter a wild Gengar deep within the vegetation of Mount Moon.
Select the trap or capture option by clicking a Poke-ball in your inventory.
Keep the wild Gengar exhausted to successfully trap it.