Special effect help needed for short video clip.

I have a short video clip of someone swinging out over a lake on a rope swing and then falling into the lake. I also have a short video clip of a fish coming out of the water and eating a small fish. I would like to have these combined so I have one clip where the person on the rope swing, swings out over the lake and then the huge fish jumps out of the lake and swallows the person. I would prefer this to be done in Adobe After effects, but any special effects program would be fine.