When I read about the challenge it got me thinking about night and day. I flipped around a couple of ideas.
Everyone knows about the Day of the Dead, so I thought about Night of the Dead. Making the lightbulb fill with a glow in the dark sugar skull, which would look rad under blacklight.
At night moths flock around lightbulbs, so I thought what if butterflies were attracted to lightbulbs in the day time.
I guess this could also work the other way around too "Día de Muertos", with the sugar skull showing up in UV ink, the butterfly in glow ink.