It's a tough thing for an actor to carry an entire movie. It's perhaps even harder to enter a movie for a short time, sometimes even a single scene, and make a significant impact. Get the right mix of character and actor, though, and magic can happen. An extremely well-developed supporting character can add new levels of enjoyment, introducing fresh energy into a story or taking what's already established and kicking it up a notch.
The following characters did just that. Their screen time might be limited, but what they do during that time makes an enormous impact. In fact, you could argue they steal the entire movie they're in. Some bring comic relief, others join in the already-occurring action, and a few provide an intriguing new angle to the story. However they do it, these characters are highlights of their respective films.
Vote for the characters you think did the most in the least amount of time.