In the video you will notice how the water rises and receeds but the creatures get taller. If you have read Bob Frissell's "Nothing in this book is true......" you will know what I'm talking about. The reason the creatures get taller each time the water rises is because each time you move up a dimensional level you get taller.
I always thought they were getting taller as, if I remember correctly, the camera is on water level and the amount of light bending would not have been so great.