To use this project, copy the Spark sprite and the custom block on the stage into your backpack. To add a spark effect to your game, simply add the spark sprite to your project and drag the custom block into a sprite.
This project is a tutorial project for http://wiki.scratch.mit.edu/wiki/Using_Clones. It uses clones to create a cool particle effect.
To try it out, press the green flag, then press space to create sparks at your mouse.