Dimmly Lit Black Saucer chased out of Gulf Shores, AL

While standing outside on a pier in Gulf Shores, AL, on Bon Secour Bay, looking Southbound, we heard what at first we thought was an 18 wheeler with a flat driving by on HWY 180.  The sound continued and grew louder, when we decided it had to be a helicopter, because we could tell it was coming from overhead.  
Right at that moment we saw what we THOUGHT was the helicopter come into view as it quickly continued NorthWest around the edge of the bay with an ACTUAL helicopter in close pursuit, as if it was trying to keep up or chase it away.  The helicopter was also not the normal as it was not as bright as your average aircraft and had orange/red lights on it as opposed to a white light.  
The craft was dimly lit, with several lights lining the length of it.  It moved extremely fast in a swaying motion, while the helicopter chased it.  It appeared to be very dark if not black in color and long/flat in shape.
At the same time, inside the house we were told by relatives that our dog was whimpering and very obviously showing concern for us being that we were outside.
Another relative who was also in the house showering was so frightened and caught off guard by the type of sound and loudness, and the amount of time that it took to get out of the area, that they had to turn off the water to listen.