They're pets. They boost your income depend on what type. What you show on the image are just a piece of armor it has. There is a bug where you could break your pets and get the armor. A real pets will boost depend on what type they are, like money pets will boost your money, token pets will boost your token, and there is miner pets (if i remember correctly) that could boost both token and money. You can only use 1 pet at a time.