The Purple Neon Maze (or Purple Light Maze) is an area accessible from the tunnel of the Highway in Onyx Tile World.
Features
The area is mainly just purple pathways arranged as a maze. There are a number of Shadow Birds in the area which transport you to a sectioned off area in Pokemon World filled with other Shadow Birds. You are unable to move here.
Grey Ghost Area
When interacting with a purple object at the end of
one of the paths, it will transport you to the Grey Ghost Area, which is simply a grey pathway with a ghost in it. When going to the other side, it transports you to an area that looks like the outside of the Hospital in Graveyard World. It also has a well. If you leave again this way, the colors become desaturated and will not readjust until you wake up.
In the newest versions (0.94a and beyond), the Purple Neon Maze is blocked off by traffic cones. It can still be accessed if you are teleported there by a chaser.