my cap is no crown, yet i have my own kingdom networks below, its own kind of freedom though i don’t swim, i may still have gills i can change your perception, dance on tongues, or kill

When raindrops dance, I stand guard forever, Shielding you from wind and weather. With a gentle twist, my arms open wide, A portable roof, where dry you abide.

Fashioned from once-living skin, I exist only through you. I have a lying tongue and a blind eye. I remember paths in dirt, forget them in rain. Useless alone, directional in pairs. I protect, carry, and end every journey before rest.

When not hidden in a box, I am seated in a hole. I only move when you do, and I'm rarely found alone.

I arrive with a twin but rarely stay together. My color warns, my taste forgives. Break me open and I betray my softness with a stone that refuses your teeth. Birds steal me first, humans argue whether I belong on stems or in jars. What am I?