As you move toward it, it moves away from you. If you retreat from it, then it will advance in your direction. It goes down if you go up. Up it goes, as you descend. It's unreachable but it's always there.

A cap above, strange gills below, through dampened woods I often grow.

Used to sign your name with, usually blue or black, Or sprayed out by a squid in a defensive attack, It used to be found dripping off the ends of quills, Or hiding under stoppers in the shallowest of wells

I have a single room but no hallway. I wear a hat of grass or dried straw. I live in forests, beaches, and wild mountains. I am a home, but I use no bricks.

I top your latte, crown the sea, and cushion you while you sleep peacefully.