What is a UFO on Howrse?

UFO's are the objects that pop up now and again that move round the screen. Lke: Apples. Turnips. Carrots. ect.. When it tells you to 'catch' a UFO on the objectives to complete, it means for you to click on the object when you see one moving around the screen. This means you now have that object in your inventory, and therefore, completed the objective.