The Hulk is about a man who changes into a green super-being as you well know!
In the movie the clip to use is the moment that the Hulk first becomes 'The Hulk' if you see what I mean. You'll need to watch it (if you can) to decide which clips to use and for how long.
The point - is that as Christians we have become followers of Jesus, members of the Kingdom of God. As part of this, we find ourselves changing to be children of God, no longer ruled by sin and self but under the authority of Jesus.. we change from the old self to the new self.
One of the most important things as a Christian is integrity - being and staying the same person - men and women of God. This means that unlike the Hulk we don't change back and forwards between 2 beings but stay the same person, a child of God.
This is hard in our lives because there are so many pressures on us to act in ways that Jesus wouldn't. There are so many temptations, many times when choosing to stand and stay as a Christian is so hard. But God promises that he will be with us and not let us get tempted beyond what we can handle.
So next time you're tempted to not act like a Christian, remember the Hulk and try to stay and stand as one of Jesus' disciples - a disciple he loves and helps to only change for the better, to be more like Jesus.