Osis (Footbag Trick Tutorial) In this tutorial you will learn the hacky sack trick Osis! Paradox MirageDown ButterflyAll Hacky Sack Tutorials Skill Toy Interests General Skill Toy Stuff Kendama Slackline Poi Hacky Sack Buugeng Balisong Contact Juggling Diabolo YoYo Freeline Devil Sticks Spin Top Balance Board Leave this field empty if you're human: