The beast tribe of Gloo is causing trouble in town and it's up to Rubba to stop them. He isn't really trained in the art of direct magical combat, but he has of photographic counter-spells. His camera allows him to capture the magic missiles cast by his enemies and shoot them right back.
When an enemy shoots a magic missile at you, you can capture it into your camera with the right timing. Each captured projectile gives you two shots of the same element to shoot the projectile back at the enemy. You can only stockpile eight shots of one type of element at a time.