Invisi-ghoul is the sixth mini-game in Plants vs. Zombies, Plants vs. Zombies: Journey to the West, and Plants vs. Zombies: Great Wall Edition. It's a conveyor-belt level unlocked by completing Adventure Mode and three other mini-games. It takes place in the Pool area at night where all of the zombies are invisible. Items from the zombies, such as ice trails from Zombonis and buckets and roadcones falling off from zombies, will be visible for a short time.