I'm not sure what you mean by "when the mousex becomes greater than the object," but I'll assume that you are comparing it to the object's X value. If you want the global('x') to be added just once, you might want to make another global numerical variable first. Let's call it 'Added' and let its initial value be zero. In your event, you have to check for 2 conditions: that mouse.x > object.x AND global('Added') = 0. You will then add 2 actions for that event. First, add 10 to global('x'). Next, set global('Added') to 1. This will guarantee that adding 10 to global('x') will occur once and only once if at all.