A bizarre video has emerged of activist Arteval Duarte hung by his feet in a box with a snake.

The footage, shot on Wednesday in Breu Branco, Brazil, shows the 'Ninja of Serpents' being hung by his feet in a box with his hands chained.

His assistant, Carlos Avelino, then proceeds to place a boa constrictor into the box with Duarte.

When Avelino opens the box, Duarte's hands are free and he is holding the snake.