While driving south on 165 near ady rd near pylesville md a solid white with green tint ball of light seemed to materialize almost in the middle of my windshield at about 15 to 20deg deflection at approximetly 1 mile or less. to the east/southeast . it popped in then descended rapidly in a straight line behind trees that were closer to me. no trail was observed. no noise could be heard in my truck. it was a bright light not brilliant. no impact flash was observed. i did not stay in the area. it did not look like airplane light nor was it moving slow enough to be an air plane. it wasn't fireworks since it had no trails and seemed to materialize then descend down and away. if i had to liken it to anything it would be firearms tracer fire. but shot from up high angled down. but the light was far to big to be tracer fire. and it's the wrong color. i knew it fit the definition of a ufo right away.