You probably didn't know the London Marathon took place last weekend, but you'll wish you had watched it after seeing this.

A little boy decided to have some fun with the runners during the race. And by "fun" we mean the kind of pranks employed by middle school bullies everywhere.

This kid is working it. Sure, he didn't break the kind of sweat the runners did, but he did strain himself working the arm muscles, with the constant sticking out and back in.

Running may do a body good, but playing a joke is the kind of workout that's good for the mind. And you may burn a few calories laughing, too.