Protesters formed 'a human chain' [=they stood next to each other with their arms linked] around the ancient tree to prevent it from being cut down.
In the United States, the President as the commander in chief is at the head of the military 'chain of command'.
I thought he really won the lottery but he was only 'pulling my chain'. [=he was only playing a joke on me]
(..) Nowhere. Gee. He looks blue. I'd say brownish-gold. No, no, no, no. I mean he's depressed. Kid, what's eatin' ya? Nothing-- he's at the top of the food chain! The food cha-haain! Ah heh-- Ahem. So, where you from? Who cares? I can't go back. Ahh. You're an outcast! That's great; so are we! (..)1994 The Lion King
(..) It's not funny, Ed. Hey, shut up! Will you knock it off! Well, he started it. Look at you guys. No wonder we're dangling at the bottom of the food chain. Man, I hate dangling. Shyeah? You know, if it weren't for those lions, we'd be runnin' the joint. Yeah. Man, I hate lions. And man are they... (..)1994 The Lion King