Been having a bit more of a play with After Effects to practice keying. Here's what I got.
Filmed in front of a green screen.
First the ball was masked out - roto style.
Generated soem particle effects in particleIllusion and dropped them in.
Motion tracked the position for the particles.
Simple flare when ball 'appears'
Added faux lighting to person for the particle effect glow and flare.
Added still image as background animated to dolly with camera. I did dolly too, no zoom.
Added faux depth of field to background image as camera dollys in.
and had a play with Andrew Kramers demon face warp tutoral to finish as the kids think it's great fun
All done in high def so if anyone desperately needs a 1080 version then let me know
Major lesson learned is to be much more careful to take a still image that matches the angle of the keyed image next time because animating the thing is a nightmare to sync with the feet and the main bit I'm not happy with.
It's just for fun so don't want to put any more effort into it but one thing I would do if I could be bothered is a reflection in the floor.