gets you: Wooden Sword
The dark matter is so small that it lets you seem like there is nothing there but there is. It's fun to fool people to by putting spikes and other dangerous stuff underneath.
First create a box out of carboard and make it so it is the height of Sackboy's shoulders.
Next, cut out the centre of the box with same shape but smaller size so you can hop in it.
(The thicker the lines the slower and harder it is to hover)