Note: This can only be done online. As a GLA General, get a Worker and build a Scud Storm to 0%. To do this, tell him to work on it then tell him to go to a different place. After that, click on the unbuilt Scud Storm. Hold Q then CTRL. While holding those keys, click where you want the Scud Storm to hit. You can do this several times and you only have to wait a few seconds between launches.