Men in Black
They are subject of movies and urban legend. They are omniscient and everywhere. This is because that the Men in Black are either (a) waiters or (b) penguins. You will able to tell waiters by their uncanny abilities to rattle off a list of unpopular specials, to hover just off your elbow to judge the quality of your conversation when unneeded and to become invisible the moment you need something. Meanwhile, penguins can be confused with waiters quite easily. However, a quick check of your 116-volume Jane's All the World's Aircraft and Penguins will confirm whether or not the creature in front of you demanding fish is a penguin.
The Men in Black were around for decades but were unknown for the longest time. That's because the Neuralyzer ("flashy thingy") was 100% effective at erasing all memories. Unbelievably, it is no longer in use or even needed since with the internet, humans' attention spans are down to nothing. Too bad for us that you didn't make it past the first sentence in this article.