Answer:
I always have to work with something in my eye.
I am what bring things together. Without me everything you see would be a total mass or debris everywhere.
What do you get when you cross a pig with a karate expert?
Marking mortal privation when firmly in place. An enduring summation inscribed in my face.
I look like a tiny trombone
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.