Gimmick Mountain is a mechanical mountain who's owner is unknown but despite this there are rumors Reuben bought the place at some point.
The Yu-gi-oh clubEdit
Reuben and Deadfish are looking for a powerful deck as they're with GEO in his forest base in Bloomindale. So then they heard rumors of a mountain that at the top has a deck of gimmick puppets. Reuben and Deadfish along with GEO carpool to Gimmick Mountain before GEO can even the door in Gimmick Mountain Deadfish and Reuben race in there Reuben narrowly gets the deck because Deadfish is too fat to platform between Gimmick Mountain gear platforms
Gimmick Mountain is not an actual mountain but a building fashioned into a building. There is many gear in the building an the building requires much plat forming to traverse recently some music was added from a different Gimmick Mountain from a game. This may have inspired Gimmick Mountain. Besides that Gimmick Mountain has many conveyor belts and has a metallic floor and often has rock to go with the fact its meant to be a mountain the place is also very large in size.
Reuben's ownership of the place.Edit
Ever since Reuben owns the place he fills it with portrait of himself and has music play. Owning the place he constantly hides out there. He also installed a loudspeaker of the place to say stupid stuff into.