Green, red & white alternating lights hovering and moving horizontally and vertically.We observed an object with oscillating green and red lights (similar to navigation lights but very different than anything we've ever seen) rising and falling vertically for a period of 5 minutes in a northeasterly direction from Holiday Marina at Lake Lanier, Buford, GA.When we first noticed the object, it appeared very high in the sky and was a stationary red light. It didn't appear to move for 20-30 seconds after we noted it. The object then began to descend and alternated a couple of times between green and red light. The object appeared to float in an unusual hover pattern and then randomly moved (very quickly horizontally before returning to its ascending and descending pattern. The light would periodically switch from red-green and then to white.The object climbed and descended a range of 20-30 degrees on our horizon at an indeterminate distance, but at least several miles away. It appeared to be the ‘type’ of maneuvering a helicopter might make, however we have never seen a helicopter appear to move in that manner. It was almost floating and then would go straight up/straight down very slow, then very fast. Sideways also. It finally disappeared below the horizon.