Baby Dry Bowser is oddly a mini boss in SBMX. He is the last mini boss and the hardest. He gets his dad to fight you, after you kill him, you beat up Baby Dry Bowser. After a while, the dad comes back, only bigger. After three trys, you can kill Baby Dry Bowser. Is you sell his "hair", it will be worth 1 ruby!

Looks a lot like Bowser Jr.