A stick that can be used in firebuilding.
Make a series of shallow cuts down a stick so that the slivers of wood feather out. They should go around the wood and up it.
These are essentially tinder and can expose the dry wood underneath if you only have wet wood.
You can strike up the stick (towards the insides of the "feathers") with a ferro rod for a no match fire.
If you can't make a feather stick easily, your pocket knife is too dull! (blade maintenance)