Dark Way

You create a ribbonlike, weightless, unbreakable bridge.
The bridge is 5 feet wide, 1 inch thick, and upto 40 feet long.
A dark way must be anchored at both ends to solid objects,
but otherwise can be at any angle. Like a wall of force, it must
be continuous and unbroken when formed. It is typically used
to cross a chasm or a hazardous space. Creatures can move
on a dark way without penalty, since it is no more slippery
than a typical dungeon floor. A dark way can support a
maximum of 500 pounds. Creatures that cause the total
weight on a dark way to exceed this limit fall through it as if it
weren't there.
You never fall through a dark way unless your own weight
exceeds the spell's maximum capacity.