Light travels in a straight line. When you stand in front of a regular mirror, the light that hits the mirror bounces back to you the right way up in a straight line. But when light hits the surface of the spoon which is curved inwards, it comes back to you at an angle and you see an upside down reflection, because the spoon is in the shape of a concave mirror.
In a concave mirror, light reflects in a different manner. The top of the mirror will reflect downwards and the bottom will reflect upwards. The left side of the concave mirror will reflect right and vice versa. The point where all the light rays meet is called the focal point and when you stand beyond this point, you will see an upside down image of yourself. If you go close enough to the spoon before the focal point, the image will actually look upright.
Picture Credit : Google
