When I tried to figure out the instant-hit laser stuff (which Ashley already solved) I created something entirely different from what I intended. I'm not sure this might be of interest to any of the advanced users around here, at least it was a little surprising to me.
I may think along the path of this example to do some explosions for another project.
Okay, maybe just try it. Click in the window to create a thingie and use the arrow keys to alter duration/intensity.