Create a New Scene

Use AnimatableBody3D as the root Node

Rename it to MovingHazard

Add a MeshInstance3D as a child

To generate the CollisionShape3D

Select the MeshInstance3D Node

In the Viewport click on the Mesh button

Click on Create Collision Collision Shape

Choose Sibling for placement

Choose Simplified Convex for type

Select the MovingHazard node

Attach a new Script

We will tween the global_position property

We need to know: 

how long the tween will take (duration)

where the tween will move to (destination)

Now create a new level by

duplicating one of your current levels

add an instance of your MovingHazard scene

in your new level scene.

Remember to add your MovingHazard to the "Floor" group

Set the File Path Property in Level 3 to point to Level 4.