I saw a video of a guy doing it as Luigi(https://www.youtube.com/watch?v=0DpEdAXJmnk), but I tried doing the same with Wario, and it's not working at all. I can't even get to mess up and fall through the floor. (and I can't do it with Luigi either, not that it matters since what I want is to clear the game as Wario)
Is there a specific set of stairs I need to stand on?
You need to stand on the second step on the left Not counting the floor. Slide into the corner. I tried it as all characters. I tried it once as mario. He went into this weird place where the screen was black. I could see the room in the distance. As Luigi, I died. As yoshi, I died. When I was wario, half the time I died, the other half wario was too fat and wouldn't fit.
Alright, thanks for the right stair. I managed to pass through the wall and die, which is a beginning, but I can't seem to get the good result. I tried beginning the slide tackle both farther and closer to the wall, but nothing changes.