Every light bulb needs to control the electricity passing through it or the bulb will just die a quick death. Our old friend, the incandescent bulb (and its brother the halogen bulb) has a filament that provides resistance to the electricity. But other lamp types -- like fluorescent lamps and any kind of HID lamp -- have no filament, so they need another way to control electricity.
This is normally done with a lighting ballast, which the electricity passes through before entering the bulb. But many of the lamp types that use ballasts are getting replaced by LED bulbs. While some LEDs are now built to use an existing ballast, they originally used something called an LED driver that basically provided the same function. And many still use them.
In fact, if you've bought LED bulbs for your home, the same thing applies -- those bulbs just have the drivers built in, while other LEDs have external drivers that may run more than one lamp at a time. While the light function of an LED may last for years, drivers can give out much sooner. This is why we recommend name brand LED bulbs for the home, especially those with 25,000 hour rated lives. You can save a buck or so on generic lamps, but these are usually made with cheaper parts including drivers, so you'll more likely run into bulbs dying early.
So what does it look like when an LED driver goes bad? It is rare indeed to see them breaking the law with bank heists or anything similar. More likely, you'll just get a pulsing light like the one seen here.
Now we can't say for sure that this pulsing light is caused by a bad LED driver. It's possible there's some other electrical problem, which is just one example of why the world needs electricians. They can assess and fix the cause of this. But we do know that the LED driver could be the source, and this at least illustrates the importance of quality components from driver (or ballast) to the light source itself.