Develop a Sprite and Platform Game - Unity 3 Game Development - page 6

There is also the Unity built-in Plane object that you can use, but you don't
really want to use it, because the Unity built-in Plane object will have way
too many triangles for our 2D objects. As we can see from the following
screenshot, our prefab Plane only has two triangles, but the Unity built-in
Plane object will have around 200 triangles.
2. In the Hierarchy view, right-click on the Plane prefab object, and choose Rename to
change the name to Background .
3. Then, click on this object and go to its Inspector view, and set its transform Position
to X: 0 , Y: 0 , Z: 24 , Rotation to X: 0 , Y: 180 , Z: 0 , Scale to X: 200 , Y: 200 , Z: 1 .
4. Right-click on the Animation component in the Inspector view and choose the
Remove Component opion to remove it, as shown in the following screenshot: