Get one long twisting balloon
Inflate the balloon, leaving a few inches uninflated at the end
Tie the balloon closed
Hold the tied end as the handle
Fold the balloon about one-third of the way from the tied end
Twist the folded section several times to form the handle guard
Twist the long section near the guard to form the blade
Shape the remaining length into a straight sword form
Adjust the twists so the sword holds its shape