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]
(..) It's Maggie's friends. Watch this. - Hey, girls, how's it going? JAIME: Do I know you? What'd you do, mug K-Fed? Welcome to the bottom of the food chain. Hey, look, you always had my back in high school, okay? So if your spirit guide wants you to be a fake teenager... (..)2009 17 Again