So I downloaded the game yesterday and played a lil until Zone 2-5. When I got to the first jump, I spaced myself a small amount away from the wall and jumped and made my ghost. When he spawned he glitched through the wall and fell all the way down. He is still vulnerable to collision, biut I couldnt manage to get him to boost the real kitty through. Maybe you already know about it? I dunno

As you described, that glitch happens when you spawn a clone very close to a wall while, at the same time, not touching it. Currently, it has no use in speedrunning though.