Since you are using the perspective tag, all you need to do is this:
-Spawn a type: 3 object with the perspective tag (in your case id: 666).
-Make that object slowly move towards the bottom of the background (use hit_j: x; x has to be bigger than 50).
-Calculate how much frames does the object need to reach the bottom and then make it go to the opoint frame.
-Spawn a type: 3 object with the perspective tag (in your case id: 666).
-Make that object slowly move towards the bottom of the background (use hit_j: x; x has to be bigger than 50).
-Calculate how much frames does the object need to reach the bottom and then make it go to the opoint frame.