how does backgournd summon objects?

[STM1993]

Check the mainsite
Basically the weapon opoints a 1st ball, which opoints a 2nd ball.

1st ball moves all the way to the z-axis front of the screen.
2nd ball moves all the way to the z-axis back on the screen.

Now 1st & 2nd ball move towards each other. If the background is correct, both balls should touch each other EXACTLY when the balls go into an activation frame.

1st ball has itr kind 9, which collides against 2nd ball's bdy.
2nd ball goes into rebounding state, and from there you can create special effects on the background.