I went outside with my dog. It was sunny with few clouds. The time was 17:30. I heard a helicopter, and looked up. A white helicopter with two rotors was going overhead. The helicopter was very low; I would estimate 150 feet off the ground. There were no markings on the helicopter. As I looked at the white copter a black oval UFO flew into my view. The UFO Sighting was small maybe six feet in length. I could see the sun glinting off of this UFO. The UFO flew directly at the white helicopter. I thought that it would collide with it. At the last moment the UFO veered away. It flew east up over the other building in our condominium complex then quickly veered south towards the Naugatuck State Forest at great speed. I continued down the hill with my dog to the end of our road. At that point, an unmarked single rotor black helicopter flew towards the Naugatuck State Forest following the path of the UFO.