Here's the interesting thing about song lyrics and poems (and other forms of literature): often, the author either a) didn't mean anything, b) doesn't know what they mean, or c) had a meaning that they were *only aware of subconsciously*. In this latter case, it takes amateur and professional audience members (the latter kind are called "critics") to decide what was meant. It's subjective, and lots of fun can be had from creatively determining what was "meant". :)
The lyric here is "Snatch your chain and mace your eyes". Not "chains". My interpretation is this: "I have a chain on your collar, like a dog, and the other end is fastened to a wall. I am going to snatch (or jerk, or pull sharply) at the chain to get your attention and then I'm going to spray mace (a form of tear gas used for self-defense) into your eyes."