Any ideas for good protest props?

A friend of mine found a baby doll and a carrier at Goodwill, put the doll in feety-pyjamas, wrapped the torso in a scarf and strapped it to his chest. It was convincing enough that when I saw him at the May Day protests in NYC, I ran up to him and asked him who's kid he was carrying because I knew he didn't have one of his own. He was like "not mine, and I am not fucking getting arrested because of it."