really quite liked the way this was put in the list, as it just mentioned blinking lights. so that left quite a bit to the imagination.
the first thing that popped into my head was lightning, so off i went on my merry little way and made some coroutines for lightning fading in and out at random times 
enjoyed this one and it put an image in my head and gave me a head start for a direction to aim for.
heres my vid (excuse my watch beeping through it doh)