A somalian woman. The protruding forehead and teeth and the lump of hair at the back which is hidden under the usual somalian costume gives the head an appearance from the side which is similar to the shape of a light bulb.
Those light bulb heads are queueing at the benefits office at 8am every Tuesday and it doesn't open until 9.
When you think you are 'straight' and meet someone of the same gender/sex that you seem to be attracted to in a romantic or sexual way. Can vary from person to person.
I've never really been attracted to girls, but this one seems like a Light Bulb Crush.