The haka is the most frightening dance you'll ever see. And that's its purpose. It's a Maori war dance, and each violent movement is designed to intimidate the enemy. It's a posture dance performed by a group, with vigorous movements and stamping of the feet with rhythmically shouted accompaniment.
The New Zealand rugby team's practice of performing a Haka before their matches has made the dance more widely known around the world.