Here is the easy answer - use Rex's moveto plugin: http://c2rexplugins.weebly.com/rex_moveto.html
Second easiest would be bullet behaviour. You'll need a "start moving" event, where you enable bullet and set the direction and speed, and a "stop moving" event where you disable bullet. The conditions for each of those are up to you. (Invisible sprites are excellent tools for this - you can set the invisible sprite as a "target" when you start and stop when you collide with it)
There are also many ways to create your own custom movement through events.