On 11/12/2019 at 1935 hrs. while outside at sigsbee park, located on dredger key. our approximate vantage point was due east of the objects location. attached is a map with a red pin indicating our location. the objections approximate location is circled in black over open water. i estimate the altitude to be over 1500 feet with moderate cloud cover visible in that same area. the distance from our location to the objects was approximately 6+ nautical miles. there was a moderate amount of moon light in the night sky to our backs. we're unaware of the actual length/time of the event. at least to the point of our observation. it lasted approximately 15 seconds from this point. the light or more so flame appear to be incapsulated in a "tube". the light was in a perfectly straight line and paralleled to the horizon. we estimate the objects length to approximately 1000+ feet from our distance. the flame in the "tube" looked as if it was chasing/leapfrogging itself, as like a moving "centipede". the direction of the moving flame(s) in the "tube" appeared to move north to south. the movement we observed during its duration was slow and controlled. the illumination appeared to fade from the front of the object, located at the south end. as it continued to fade, the last three flames appeared to be rotating fireballs or orbs. these three orbs appeared evenly placed in the "tube". there were no aircraft in the area at the time or no observed lightening storms/events. the objections color appeared to be orangish-red. note: the key west airport and naval station key west are located near by. i'm not an aviator but, have been extensively exposed to aircraft of all types. especially, military aircraft and airborne operations. i've never observed anything remotely similar to this sighting. this includes flares of all sorts and military aircraft counter measures. there was no sound, as to jet aircraft. it wasn't aircraft "afterburner" either. the following morning we boated out to the approximate location of the sight. we didn't observe anything in the air or water that appeared abnormal. no oil slick or debris in the water.