|The False wall glitch|
This glitch involves mapmaker, so fire that up and make a new map, and make sure the tile set is Industrial.
Put down adapter 3 (crab ramp), and the put a large pit next to it, (So the bottom of the ramp is next to the top of the large pit.) Go halfway up the crab ramp and face the large pit wall. You can do this either side. Run straight into it, and you will fall through the wall and see only pitch black, you will also die. So, put down a small room, like a double corridor. Once you do that you will be able to stand in the pitch black, because technically, you are in the double corridor.
Now, put a teleport at the end of the corridor and another somewhere else, and then try going through it. This can take a few minutes to find it, since you still can't actually see it. Once you find it, you will teleport to the other teleport you put down, and you can see everything again!
Go back through the teleport, and you will be in the double corridor.
This can be used to make secret areas with lots of weapons or powerups to use against your friends!
If someone could test this with other tile sets, I'd be happy for you to put it down here.