How did that just happen!!!?

What the

I have recently been thinking about how fun it would be to go around town with a somewhat high powered laser pointer (300MW or so) to pull pranks on people and watch their reaction to the fun pranks you can do with a laser pointer. For example: Popping water balloons from a distance on a public sidewalk, putting a small random firework (sparkling kinds though, for no accidental injuries) on a public place and lighting it while hiding behind something, maybe setting a newspaper on a table on fire that will attract peoples attention.
Basically just seeing peoples reactions to the spontanious combustions around them. sound fun?
NOTICE: I do not own the youtube video in the link, just an example of one of the prank ideas from above.