This Boo doesn’t seem mean at all, in fact, he has a big grin on his face. Boo first appearing in Super Mario Bros 3 for the NES and is widely known for terrorizing Mario when he is not looking at him. When you do look at Boo, he plays peek-a-boo and covers his face because he thinks that you do not see him. This Boo Balloon is a neat idea that was put together quickly and colorfully by a Nintendo enthusiast.