I was sitting on my front porch just looking out east,sort of ne, when i noticed it. being that the airport flyway is close by for landings, i first thought it was a plane coming into land, but it wasn't right,it wasn't flying toward the airport ,it was heading more to the southeast. i see these planes coming into land all the time and when i do,you can see them coming in from the north, decending to the south,and they're usually about 7 or 8,000 ft up and dropping. what made this different was not only was it not decending, it was much higher, maybe about 25-30,000, ft up. it was moving in a straight line, heading se,probably for about 30 or 40 seconds ,then it just stopped.It stayed in one place for about 15 seconds,and then it dropped about 1000 ft, stopped again, moved south,then north, then dropped again about another 1000ft, then sped up and went back to the ne at a higher speed and went right into a huge cloud and dissapeared. all of this happened in about a minute and a half or so, i remember thinking about going in to get my binoculars, but didn't want to take my eyes off it. after it dissapeared, i kept watching, but it either was hanging out in that huge cloud or it vanished. i watched for about another 20 ,minutes or so, and even when the cloud had dissapaited some, it was gone.I could tell that it was rather large, due to the planes that i see in the flight path to land at dia all the time, and i would estimate this object to be at least 500 ft long and about 50ft high. any questions, call me . thanks.