[douglas]

Note: for moving through warp points on the same turn as you open them, it's a good idea to have the warp opener be one sector away from the moving ships and explicitly order the moving ships to move to that spot before moving to the target system.

Star Destroyer: Open warp point and send ship to target star. You'll have to wait for the next turn to trigger it, and if he happens to have anything at the star or right next to it, he might be able to stop it.

Nebula Creator: Send ship to star in system with warp opener. Once nebula creator is at star, issue the open warp point order and tell the nebula creator to move to the target star and blow it up. If he happens to have anything at the star, which is quite likely if he's started building ringworlds or is on his guard against things like this, it will fail.

Black Hole Creator: Send ship to star in system with warp opener. Once BH creator is at star, issue the open warp point order and tell the BH creator to move to approximately where you think the other end of the warp point will be and then create a black hole. Unless you have extremely bad luck and he just happens to have something in that sector at the wrong time, this will work. It would be a good idea to have a star creator standing by to replace the star the BH creator started at.