Driving on hwy 75 heading south going to Sergeant Bluff . Just prior to a set of stop lights saw an object that looked on fire above the hillcrest shopping center main building.thought that it was a hot air balloon but quickly realized the object was too small. I've seen a hot air balloon up close before but this object was too small to be a hot air balloon. Then thought it might be a Chinese lantern that are lit on the 4th of July that glide in the wind but the object was way too big for that. I pulled into the shopping center and stopped in the parking lot facing the main building's Westside wall. I watched it looking from side to side trying to get a better look and judgement of size. I determined that it was about the size of a large commercial size cement truckmixer-the cylinder part that turns. May be a bit bigger. It did not have any sound,no heat, and did not move just hovered. It looked like it was on fire reddish orange on the outside,orange yellow with a little white as if it was super burning hot inside. It appeared to be radiating fire flames but the flames didn't leap off but rather seemed to return or roll back into the center like it was feeding itself. Decided to move to get a better look. Moved the car into the parking spaces on the north side of the main building.and then it disappeared. I got out and looked straight up to see if it was above me. I looked every direction,clear skies, it was gone.