Creating a random move,velocity and visibility of an image

Hi i am using particle candy to make some effects, it is great and works very good, now i am trying to create a particles that will appear and disappear, moving by a random algorithm it should be a very little star that flashes and appear and disappear and move, or some like world of goo, on the main menu he has some goo balls moving

see the little goo black balls moving, need some help to star creating it

http://www.youtube.com/watch?v=pa5bfs8tNqc [import]uid: 26056 topic_id: 18494 reply_id: 318494[/import]